Construction calculator glossary: building terms & formulas

Air conditioning tonnage measures cooling capacity, where one ton equals 12,000 BTU per hour of heat removal needed for indoor square footage and climate load.

ADA Ramp calculates ADA-compliant ramp length, slope, and landing requirements from the rise required to cover.

ADU Cost estimates cost to build an accessory dwelling unit by type and sizes, including permits and fees, plus rental-income payback and ROI.

The organization, office, or individual responsible for enforcing building codes and permit requirements in a given area. Could be a local building department, fire marshal, or state agency.

Air changes per hour (ACH) measures how many times the total air volume in a room is replaced with filtered or outside air within 60 minutes.

Aluminum Weight calculates weight of aluminum bar, plate, sheet, or tube from its dimensions using 0.0975 lb/in³ (2,700 kg/m³) aluminum density.

The SI unit of electric current. One ampere is the flow of one coulomb of charge per second through a conductor.

Angle Iron Weight calculates weight of steel angle iron (L-shape) from its leg dimensions, thickness, and length.

Artificial Turf Cost estimates artificial turf cost with materials takeoff, install labor, and a 10-year comparison vs natural sod including water savings and rebates.

Asphalt calculates tons of hot-mix asphalt needed for a driveway or lot from area, thickness, and density, with a waste allowance.

Baluster Spacing calculates number of balusters and the spacing between them for a stair railing so no gap exceeds the 4-inch code maximum.

Baseboard & Trim calculates baseboard and trim linear feet for multiple rooms including door and window casings, waste factor, and lumber cost.

Milliamp-hours, a measure of a battery's charge storage capacity. A higher mAh rating means the battery can power a device for longer before needing a recharge.

Bend Allowance calculates bend allowance for a sheet metal bend from the bend angle, inside radius, material thickness, and K-factor, for accurate flat-pattern layout.

Bend Deduction calculates bend deduction for a sheet metal bend from the setback and bend allowance, for mold-line flat-pattern layout.

A birdsmouth cut is a notched triangular joint cut into a rafter enabling it to rest flat on a wall top plate, consisting of a seat cut and a heel cut.

Blown-In Insulation calculates blown-in cellulose or fiberglass insulation bags needed for attic or walls by R-value target and square footage.

Board and Batten calculates number of vertical battens and board spacing needed for a board-and-batten accent wall from its width and desired batten spacing.

A board foot is a specialized volumetric unit for lumber equal to one square foot of nominal one-inch-thick wood (144 cubic inches), used for pricing and estimating timber.

Boiler sizing estimates the heating capacity in BTU per hour required to heat a building based on climate zone, square footage, and insulation heat loss.

Bolt Circle Layout calculates X/Y coordinates of evenly spaced bolt holes on a bolt circle (BCD) from the number of holes, diameter, and starting angle.

A unit of heat energy. One BTU is the amount of energy needed to raise the temperature of one pound of water by one degree Fahrenheit. Used to rate air conditioners and heating systems.

Building Permit Fee Estimator estimates building permit fees for home renovations, additions, new construction, electrical, plumbing, and HVAC projects.

Carpet calculates carpet square yards for multiple rooms with waste factor, roll width planning, pad and installation cost estimate.

A formal document that modifies the original scope, cost, or schedule of a construction contract. Change orders can add or delete work and must be approved by all parties before work proceeds.

Closet Shelving calculates linear feet of shelf and closet rod needed for a reach-in or walk-in closet from its dimensions and shelving layout.

Column Load calculates column load capacity for wood, steel, and concrete columns — with slenderness ratio, LRFD factored loads, and utilization ratio.

A measure of concrete's ability to resist compressive loads before crushing, expressed in pounds per square inch. Standard residential concrete is 2,500–4,000 PSI; structural applications may require 5,000+ PSI.

Concrete mix is a proportional blend of cement, sand, gravel aggregate, and water that cures into a durable, load-bearing construction material with specific compressive strength ratings.

Design a concrete mix by target PSI using the ACI 211.1 absolute volume method.

Conduit Fill calculates conduit fill percentage per NEC standards.

Copper Weight calculates weight of copper bar, sheet, tube, or pipe from its dimensions using 0.323 lb/in³ (8,940 kg/m³) copper density.

Countersink Depth calculates countersink depth needed for a flush screw head from the screw head diameter and the countersink included angle (82° or 90°).

Countertop calculates countertop square footage by section with material cost, edge linear feet, and backsplash for granite, quartz, marble, and laminate.

The area that a given quantity of material (paint, mulch, tile) can cover. Typically expressed in square feet per unit (gallon, bag, box).

A short stud wall between the foundation and the first floor of a building. Cripple walls can be a seismic weakness and may require shear panel reinforcement in earthquake zones.

Crown Molding calculates crown molding linear feet for multiple rooms with waste factor, piece count, miter angles, and cost estimate.

A unit of volume equal to 27 cubic feet (3ft × 3ft × 3ft). The standard measurement for ordering bulk materials like concrete, mulch, gravel, and soil.

Cubic Yard calculates cubic yards for concrete, gravel, soil, or mulch from length, width, and depth — with waste, weight in tons, and total cost.

Cut & Fill calculates cut and fill earthwork volumes for site grading — balance analysis, swell/shrink factors, haul quantity, and equipment guide.

The permanent, static weight of a structure itself — including framing, sheathing, roofing, flooring, and fixed equipment. Dead loads do not change over time and must be accounted for in structural design.

Deck Load Capacity evaluates whether deck can support a hot tub: pounds per square foot vs code, a pass/fail verdict, and what reinforcement it would need.

A unit of volume for lumber equal to a board 1 foot long, 1 foot wide, and 1 inch thick. Used to estimate decking material needs based on deck dimensions.

Demolition Waste calculates demolition debris weight in tons and volume in cubic yards by material type — with disposal cost options and recycling guide.

Door Sizing calculates door rough opening dimensions, header size, ADA compliance clearances, and framing materials for any door size and type.

Drain Slope calculates drain pipe slope in inches per foot, check IPC/UPC code compliance, and compares flow velocity for 2–6 inch pipes.

Drop Ceiling calculates suspended ceiling tiles, main runner pieces, cross tees, wall angle, and hanger wire for 2×2 or 2×4 tile grids.

Drywall calculates drywall sheets, joint compound, tape, and screws for any room with GA-214 finish level guide.

Dumpster Size calculates debris volume and recommended dumpster size for renovation, roofing, or demo projects by material type and weight.

A legal right to use another's land for a specific purpose. Common examples include utility easements (allowing power lines to cross property) and access easements (providing a path to landlocked parcels).

Electrical Panel Load calculates residential electrical panel load per NEC Article 220 with demand factors, service sizing, and capacity analysis.

Electrical service upgrade calculations determine whether a residential 100-amp panel must be upgraded to 200-amp service to safely support modern EV chargers, heat pumps, and induction ranges under NEC 220.

Elevation Grade calculates grade (slope) percentage, ratio, and angle between two elevation points from the rise and run, for drainage, roads, or grading.

Energy Savings Estimator estimates annual energy savings and payback period for insulation upgrades, window replacements, and air sealing by climate zone and fuel type.

Epoxy Garage Floor estimates epoxy garage floor coverage and cost: gallons and kits by coat and mil thickness, flake pounds, and epoxy vs polyaspartic cost comparison.

In construction, a decorative plate that covers the hole where a pipe passes through a wall or floor. In electrical work, a cover plate for switches and outlets.

EV Charger Sizing sizes EV charger circuits per NEC 625 — breaker size, wire gauge, panel capacity, and charging time for Level 1 and 2 EVSE.

Feed Rate Calculator calculates machining feed rate (IPM) from spindle RPM, feed per tooth, and the number of flutes on the cutting tool.

Fire flow is the rate of water flow in gallons per minute (GPM) required to extinguish a major fire in a building based on square footage, construction type, and ISO standards.

Fixture Unit calculates total drainage fixture units (DFU) and water supply fixture units (WSFU) to size drain stacks and supply pipes per IPC/UPC code.

Flat Bar Weight calculates weight of flat bar stock from its width, thickness, and length, with a material density picker.

The base structure below a foundation that distributes the weight of a building across the soil. Footings are typically wider than the wall or column above them and extend below the frost line.

French Drain calculates french drain materials and pipe sizing.

The maximum depth at which soil freezes in a given climate zone. Footings, foundations, and water lines must extend below the frost line to prevent heaving damage caused by freeze-thaw cycles.

Furnace Sizing sizes a gas furnace or heat pump by climate zone, floor area, and insulation quality — output BTU/hr, AFUE efficiency, and 20-year fuel cost comparison.

A measurement of wire diameter. In the American Wire Gauge (AWG) system, lower numbers indicate thicker wires. Wire gauge determines current-carrying capacity and resistance.

Generator Sizing sizes a backup generator by power requirements.

Gallons per minute (GPM) measures volumetric fluid flow rate through plumbing pipes based on internal pipe diameter and fluid velocity.

A reinforced concrete beam that sits at or near grade level to support wall loads and tie together isolated footings. Commonly used in post-tensioned slab foundations and frost-protected shallow foundations.

Grass Seed calculates grass seed pounds needed by lawn area.

Gravel & Aggregate calculates gravel, crushed stone, and aggregate in tons and cubic yards with truck loads and cost estimator.

Ground Fault checks NEC 2020 GFCI and AFCI requirements by room type — determine required outlet count, applicable code sections, and protection costs.

The amount of grout needed to fill joints between tiles. Depends on tile size, joint width, tile thickness, and total area. Usually measured in pounds per square foot.

Grout Coverage calculates pounds of grout needed for a tile job from the tile size, joint width, joint depth, and total tile area.

Gutter Size sizes gutters and downspouts by roof drainage area.

A structural beam installed horizontally above a door or window opening to transfer load around the opening to the jack studs on either side. Header size depends on the span width and load above.

Heat Loss calculates heat loss or heat gain through any wall, ceiling, window, or floor assembly — U × A × ΔT with annual cost and insulation upgrade ROI.

Heat pump versus gas furnace operating cost models compare annual home heating expenses based on heat pump coefficient of performance (COP), furnace AFUE efficiency, and local utility rates.

Home Remodel ROI evaluates which home renovations add the most resale value: enter project cost and calculates the recoup percentage and net equity change from 2026 Cost vs Value data.

HVAC Duct Sizing sizes round and rectangular HVAC ducts using ASHRAE equal friction or velocity method — velocity checks, pressure drop, and rectangular equivalents for any CFM.

HVAC Load Calculator calculates residential heating and cooling loads using Manual J simplified method — BTU/hr by envelope, windows, infiltration, climate zone, with furnace and AC sizing.

An HVAC ton is a unit of cooling power equal to 12,000 BTUs per hour, equivalent to the heat extraction rate required to melt one ton of ice in 24 hours.

A measure of thermal resistance — how well a material resists heat flow. Higher R-values indicate better insulating capability. Recommendations vary by climate zone and building location.

Insulation R-Value calculates insulation R-value requirements by IECC climate zone with material quantities, thickness, cost, and energy payback.

Irrigation sizes sprinkler zones and calculates water requirements.

Job Costing calculates project bids with materials, labor, equipment, overhead, and profit margin.

Joint Compound calculates joint compound gallons, tape, and corner bead for any room — with finishing level guide and material cost estimates.

Joist span is the maximum allowable horizontal distance a floor or ceiling joist can bridge between load supports without exceeding structural deflection limits.

The SI unit of energy. In electrical terms, one joule equals one watt-second. Used in physics and engineering to quantify work, heat, and electrical energy.

K-Factor Calculator calculates K-factor (neutral axis ratio) for a sheet metal bend from the material, bend radius, and thickness, with solutions for it from a known bend allowance.

A unit of electrical energy equal to one kilowatt of power used for one hour. The standard billing unit for household and commercial electricity consumption.

The minimum voltage required for current to flow through an LED. Varies by LED color: red (~1.8V), green (~2.2V), blue/white (~3.2V). Determines the series resistor value.

Lighting Layout calculates recessed light fixture count and spacing for any room using the zonal cavity method — foot-candles, lumens, and grid layout.

The variable weight a structure must support from its occupants, furniture, and temporary loads. Residential floors are typically designed for 40 PSF live load; decks are typically 60 PSF.

A wall that carries structural loads from the roof, upper floors, or beams above it down to the foundation. Removing a load-bearing wall without proper header or beam support can cause structural failure.

Log Weight calculates weight of a log from its diameter, length, and wood species, using green (freshly cut) or dry density.

Lumber Weight calculates weight of dimensional lumber from its nominal size, length, quantity, and species, using board-foot weight tables.

A concrete masonry unit (cinder block), the standard hollow concrete block used in foundation walls, retaining walls, and above-grade construction. Standard size is 8×8×16 inches nominal.

Material Removal Rate calculates material removal rate (MRR) for milling from the depth of cut, width of cut, and feed rate, plus estimated machining time.

Metal Weight calculates weight of a metal bar, plate, sheet, or tube from its dimensions and a material density picker (steel, aluminum, copper, brass, and more).

Mini-split sizing determines the required BTU cooling and heating capacity for ductless heat pumps based on room square footage, climate zone, and ceiling height.

Miter Angle Cut calculates compound miter saw angle (miter and bevel) needed to cut crown molding or angled framing at a corner and spring angle.

A material installed to prevent water vapor or liquid water from passing through walls, floors, or foundations. Also called a vapor barrier or vapor retarder, though these have different permeance ratings.

The space between bricks or blocks filled with mortar. Standard joint widths are 3/8 inch or 1/2 inch. Joint style (concave, flush, raked) affects wall appearance and weather resistance.

Mortar Mix calculates number of mortar bags needed for a brick or block wall from the unit count (or wall area) and joint thickness.

The recommended thickness of mulch applied around plants and garden beds. Typical depth is 2-4 inches. Coverage calculation converts area and depth to cubic yards of material.

The SI unit of electrical resistance. Defined by Ohm's Law: V = I × R, where one ohm allows one ampere of current when one volt is applied.

Patio calculates pavers, gravel, and materials for a patio.

Paver calculates how many pavers required for a patio or walkway from area and paver size, plus base gravel, sand, and joint sand.

Pipe Size calculates pipe diameter for water supply or drainage.

Pipe Weight calculates weight of a metal pipe or tube from its outer diameter, wall thickness, length, and material density.

Pitch Diameter calculates pitch diameter of a screw thread from the major diameter and pitch, or the pitch diameter of a gear from the number of teeth and diametral pitch.

Pond Liner calculates pond liner dimensions (length x width), volume in gallons, pump GPH requirement, and liner type comparison for garden ponds.

Pool Chemical Dosing calculates exact chemical doses for chlorine, pH, alkalinity, CYA, and calcium hardness — with Langelier Saturation Index water balance.

Pool Pump Sizing calculates pool pump GPM requirement, total dynamic head, recommended HP, and operating costs — compare single-speed vs variable-speed pump savings.

Pool Volume calculates pool volume in gallons for rectangle, oval, round, L-shape, and kidney pools — with chemical dosing guide and heating cost estimate.

Post Hole calculates concrete bags needed for post holes by diameter and depth — 60 lb vs 80 lb bags, cubic feet, and frost depth reference.

A unit of pressure used in construction to rate concrete strength. Common ratings: 2500 PSI (residential), 3000 PSI (driveways), 4000-5000 PSI (commercial/structural).

Punch Force calculates punching (shearing) force required to punch a hole in sheet metal from the perimeter, material thickness, and shear strength.

Radiant Floor Heating sizes a radiant floor heating system: BTU per square foot, PEX tubing length and loop count, and electric vs hydronic install and running cost.

Reinforcing steel bars embedded in concrete to increase tensile strength. Rebar size and spacing depend on the structural requirements of the concrete project.

Rebar calculates rebar quantities, weight, lap splices, and cost for slabs, walls, and footings per ACI 318.

Refrigerant Charge calculates total refrigerant charge for split systems based on capacity and line set length — with superheat/subcooling targets for R-410A, R-22, and R-32.

The opposition to electric current flow in a circuit, measured in ohms. Determined by material, length, cross-sectional area, and temperature of the conductor.

A system of colored bands on resistors that encode their resistance value and tolerance. Standard codes use 4, 5, or 6 bands in a defined color-to-number mapping.

Retaining Wall calculates retaining wall blocks and materials needed.

The horizontal framing member at the peak of a gable roof that the upper ends of rafters are fastened to. A ridge board is not a structural ridge beam — it simply provides a nailing surface.

A rolling pipe offset calculates the pipe travel length needed when plumbing changes elevation and horizontal direction simultaneously using 45-degree fittings.

Roof pitch measures the steepness of a roof slope expressed as the vertical rise in inches per 12 inches of horizontal run (such as a 4:12 or 6:12 slope).

Roof truss geometry calculates the precise lengths and angles for top chords, bottom chords, and internal web bracing based on span and roof pitch.

The framed opening in a wall for a door or window, sized slightly larger than the unit itself to allow for shimming and leveling during installation. Typically 2 inches wider and taller than the door or window size.

Sand calculates cubic yards and tons of sand needed for a project from area and depth, plus the number of bags required.

Sealant and Caulk calculates how many tubes of caulk or sealant required from the total joint length and the bead width and depth.

Seasonal Energy Efficiency Ratio — a measure of air conditioner efficiency calculated as cooling output divided by energy input over a cooling season. Higher SEER = more efficient.

Septic Tank Size sizes septic tank and drain field by bedrooms.

The minimum required distance between a structure and the property line, established by local zoning ordinances. Front, side, and rear setbacks vary by zone and lot type.

A wall designed to resist lateral forces from wind or earthquakes by transferring these forces to the foundation. Typically sheathed with structural panels (plywood or OSB) and heavily nailed to a specific pattern.

Shed calculates shed framing lumber, sheathing, siding, and roofing materials with cost estimate for gable, shed, and gambrel roof styles.

Sheet Metal Weight calculates weight of a sheet metal panel from its gauge (or thickness), dimensions, and material, with a gauge-to-thickness lookup table.

The area one bundle or square of roofing shingles will cover. One roofing square equals 100 square feet. A bundle typically covers about 33.3 square feet.

Shiplap calculates number of shiplap boards needed to cover a wall from the wall dimensions, board width, and reveal (overlap) width.

Snow Load calculates roof snow load in pounds per square foot from ground snow load, exposure, thermal, and slope factors.

Sod calculates sod pallets needed for lawn area.

The underside of a roof overhang, stair, or arch. Roof soffits often contain ventilation slots that allow air into the attic to prevent moisture buildup and maintain proper insulation performance.

Solar Panel Size calculates how many solar panels required by usage.

Sonotube Concrete calculates concrete volume needed to fill a sonotube (cylindrical concrete form) from its diameter and height, in cubic feet, cubic yards, and bags.

Soundproofing calculates wall STC rating and noise reduction for common drywall assemblies — compare soundproofing options and estimates material costs.

Spindle Speed calculates machining spindle RPM from the surface footage (SFM) or surface meters per minute (SMM) and the tool or workpiece diameter.

Spiral Staircase calculates number of treads, rise per tread, and rotation angle for a spiral staircase from the total rise, diameter, and desired number of turns.

Spray Foam Insulation calculates spray foam board-feet, depth, DIY kit count, and professional cost for open-cell or closed-cell foam by R-value target.

A unit of roofing area equal to 100 square feet. A 2,000 sq ft roof contains 20 squares. Roofing materials are priced and estimated per square.

The area of a space measured in square feet. Calculated by multiplying length by width for rectangular areas. Essential for flooring, painting, and material estimation.

Square Footage calculates square footage of a room or project by shape, add multiple areas, subtract openings, and estimates material cost with a waste buffer.

Staircase calculates stair rise, run, stringer length, and angle with IRC R311.7 compliance checks — materials list for treads, risers, and stringers.

Steel Plate Weight calculates weight of a steel plate from its length, width, and thickness (or gauge), plus weight per square foot.

Steel Weight calculates weight of steel bar, plate, or beam stock from its dimensions using 0.2836 lb/in³ (7,850 kg/m³) steel density.

Stone Weight calculates weight of a stone slab, block, or volume of loose stone from its dimensions and stone type, using per-type density.

The space between two adjacent wall studs. Standard stud bays are 14.5 inches wide (for 16-inch on-center framing) and are the cavities filled with batt insulation in most wood-frame walls.

Sump pump sizing calculates the required flow capacity in gallons per minute (GPM) from basement water inflow rate and total dynamic head.

Tap Drill Size calculates tap drill size for a threaded hole from the major diameter, pitch, and desired percentage of thread engagement.

Thinset Mortar calculates number of thinset mortar bags needed for a tile job from the tile area, trowel notch size, and tile size.

Thread Pitch converts threads per inch (TPI) and metric thread pitch (mm), and calculates lead for single- and multi-start threads.

Thread Size references major diameter, minor diameter, pitch, and recommended tap-drill size for a UN (inch) or metric screw thread.

The horizontal framing members nailed to the top of wall studs. Most walls have a double top plate that ties walls together, transfers roof loads, and provides bearing for ceiling joists.

Topsoil calculates cubic yards of topsoil for landscaping.

Trench calculates trench excavation volume in cubic yards with side slopes, swell factors, spoils weight, and OSHA safety requirements.

Trim Miter Angle calculates miter saw angle needed to join two pieces of trim or molding at a corner, from the wall corner angle.

True Position calculates true positional tolerance (GD&T true position) of a hole from its X and Y deviation from the theoretical exact position.

A material with very low permeance that blocks moisture vapor from passing through building assemblies. Required on the warm side of insulation in cold climates to prevent condensation within walls and ceilings.

Ventilation Rate calculates required ventilation rates per ASHRAE 62.1 (commercial) and 62.2 (residential) — CFM, ACH, and zone-by-zone outdoor air requirements.

Vertical Curve calculates elevation along a parabolic vertical curve (crest or sag) for road or site grading from the entry and exit grades and curve length.

The electrical potential difference between two points in a circuit, measured in volts. It is the 'pressure' that pushes electric current through a conductor.

A circuit with two resistors in series that produces an output voltage proportional to the input voltage. Used in sensor circuits, reference voltages, and signal conditioning.

The decrease in electrical potential along a conductor due to resistance. Significant voltage drop causes equipment underperformance. Determined by wire gauge, length, and current load.

The ratio of the mass of water to the mass of cement in a concrete mix. Lower W/C ratios produce stronger, more durable concrete. Typical ratios range from 0.40 (high strength) to 0.65 (general use).

Wainscoting calculates number of panels, rails, and stiles needed for a raised-panel or flat-panel wainscoting wall from its width and height.

Wallpaper estimates wallpaper rolls needed for any room.

An additional percentage of material ordered beyond the calculated need to account for cutting waste, breakage, and errors. Typically 5-15% for construction projects.

Water Heater Size sizes water heater by household demand.

Diagnose water pressure and calculates friction losses.

Water softener sizing determines the required ion-exchange grain capacity for a home based on water hardness grains per gallon (GPG) and household size.

The SI unit of power equal to one joule per second. In electrical terms, watts = volts × amps. Used to rate the power consumption of appliances and devices.

Watts to amps electrical conversion calculates electrical current (amperes) from power (watts) and voltage (volts), accounting for power factor in single-phase and three-phase AC circuits.

Weatherstripping calculates weatherstripping length needed, air leakage reduction, and annual energy savings for doors and windows by gap size and strip type.

Wind Load calculates ASCE 7 wind loads for buildings — velocity pressure, design wind pressure by zone, and total base shear for exposures B, C, and D.

Window Energy calculates annual heat loss cost through windows by U-value — compare single, double, and triple pane with ENERGY STAR compliance check.

Window U-Factor compares window U-factors to calculate annual heat loss reduction, energy savings, and payback period for window replacements.