Live tools 95

The numbers every project actually needs.

Concrete, framing, electrical, HVAC, roofing, plumbing, and every trade in between — measure once, order right.

No ads · No signup · No paywall · Instant results · Always free

Materials · 9 tools

Order the right pour, every time.

Concrete, asphalt, gravel, mulch — see exact volume and bag counts before you call the supplier.

Flagship · Volume visualizer

Concrete Slab Calculator

Drag the slab dimensions — the 3D model and bag count update instantly.

Length 24 ft
Width 12 ft
Depth 4 in
3.56yds³ · 160 80lb bags · $880 Open full calculator
Mix ratio

Concrete Mix

Portland, sand, and aggregate ratios for the right PSI — by batch volume.

1 : 2 : 3standard 3,000 PSI mix
Framing math

Board-Foot Lumber

Pick board size and count — instant board-feet and a material cost estimate.

Boards 10 boards
Length 8 ft
53.3bd ft · est. ~$31 Open full calculator
HVAC · 7 tools

Right-size by climate zone.

BTU sizing varies wildly by latitude — pick your zone and room size to get the actual heating/cooling target.

Climate-aware sizing

HVAC BTU by Climate Zone

Five US climate zones map to BTU-per-square-foot multipliers. Pick yours, drag the room area, get an exact target.

Area 400 ft²
14,400 BTUZone 3 · Central · 36 BTU/ft² × 400 ft² Open full calculator
Heating output

Furnace Sizing

Right-size BTU output by climate, square footage, and insulation level.

~64k BTU2000 ft² · Zone 4
Guided journeys

Bigger than one calculator? Follow the flow.

Multi-step paths that string the right construction tools together in the order most people actually use them — with your numbers carried from step to step.

Outdoor · 5 tools

Decks, patios, fences — built to spec.

Plan board counts, post layout, and bag-counts for outdoor projects.

Deck materials

Deck Material Calculator

Joist count, decking boards, fasteners, and post hole concrete — every line item before you hit Home Depot.

86 boards12×16 deck · 16" o.c.
Boundary

Fence Calculator

Post count + rail length + picket spacing — by run length and style.

18 posts150 ft · 8 ft o.c.
Electrical · 14 tools

Wire it right the first time.

Wire sizing, voltage drop, conduit fill, and panel load — the NEC math that keeps inspectors happy.

Flagship · NEC sizing

Wire Size Calculator

Pick amperage and distance — get the minimum AWG that meets the 3% voltage-drop rule.

Amperage 20A
Distance 50 ft
#10 AWGcopper · 2.1% drop · upsized for VD Open full calculator
NEC 210.8

Ground Fault (GFCI)

Where GFCI/AFCI protection is required and the trip-current thresholds by location.

5 mAClass A GFCI trip
Roofing · 4 tools

Bundles, squares, and pitch.

Shingle bundles, gutter sizing, and pitch-to-rise translations for any roofline.

Flagship · Pitch-aware

Shingles Calculator

Set the roof area and pitch — waste factor adjusts automatically for steep slopes.

Roof Area 2,000 ft²
7120.0 sq · 17% pitch waste Open full calculator
Drainage

Gutter Size

Match gutter capacity to roof area + rainfall intensity.

6" K-style1800 ft² · 5"/hr
More roofing tools 2 more
Plumbing · 7 tools

Pipe size, drain slope, septic load.

Sizing the carry pipe right the first time saves digging twice.

Landscaping · 5 tools

Lawn, beds, and irrigation.

Coverage flagship

Sod Calculator

Drop your yard area in — pallet count, square-yard total, and a ballpark cost from the local average pop out instantly.

Area 2,000 ft²
$/pallet $150
5 pallets~222 yds² · $750 est. Open full calculator
Seed coverage

Grass Seed

Pounds of seed by lawn area and grass type — new-lawn vs overseed rates.

~16 lb2,000 ft² · new lawn
Flooring & Walls · 4 tools

Tile, plank, paint — square-footage math.

Coverage flagship

Paint Calculator

Room dimensions in, gallons + cost out — counts walls, accounts for coats, and assumes 350 ft²/gal coverage.

Length 14 ft
Width 12 ft
Coats 2 coats
3 gal468 ft² walls · 2 coats Open full calculator
Box math

Tile Calculator

Box count from total area, tile size, and waste factor.

~3 boxes200 ft² · 12"×12" · 10% waste
More flooring & walls tools 2 more
Decide between

Two good options? See the head-to-head.

Key terms & formulas

The construction vocabulary, decoded.

Every definition links to the calculator that puts the term to work. Browse the full glossary →

Cubic YardThe standard ordering unit for ready-mix concrete. One cubic yard equals 27 cubic feet and weighs approximately 4,050 lbs. PSI RatingThe compressive strength of cured concrete in pounds per square inch. Residential slabs typically use 3,000–4,000 PSI concrete. BTU (British Thermal Unit)Heat quantity used in cooling capacity. In AC sizing, BTU/hr shows how fast a unit can remove heat from a room. SEER (Seasonal Energy Efficiency Ratio)Seasonal cooling output divided by seasonal energy use. It better reflects annual efficiency than fixed-condition EER. AmpacityThe maximum current a wire can safely carry without overheating, determined by insulation type, ambient temperature, and the number of conductors in a conduit. Voltage DropThe loss of voltage along a wire due to its inherent resistance over a given length. Excessive voltage drop causes dim lights, slow motors, and wasted energy. NECNational Electrical Code — the U.S. standard governing wire sizing, overcurrent protection, and all electrical installation practices in residential and commercial buildings. Roofing SquareA unit of measurement equal to 100 sq ft of roof surface. All shingle quantities are expressed in squares. Waste FactorThe percentage added to account for cuts, trim, and starter course consumption, ranging from 10% for a simple gable to 25% for a complex multi-valley roof. Board Foot (BF)A unit of lumber volume equal to a piece 1 inch thick, 12 inches wide, and 12 inches long — that is 144 cubic inches. It is the standard pricing unit for dimensional and hardwood lumber in the United. Drain Fixture Unit (DFU)A dimensionless value assigned to each plumbing drain fixture that represents its wastewater flow contribution. IPC Table 703.2 converts total DFU counts to minimum drain pipe diameters. Pallet CoverageA standard sod pallet holds approximately 50 rolls, covering about 450 sq ft total. Coverage varies by supplier and roll size, so always confirm the exact sq ft per pallet before placing your order.
Concrete (yd³) = (length ft × width ft × depth ft) / 27Slab volume in cubic yards — what the ready-mix dispatcher asks for. Order 5–10% extra for spillage and uneven subgrade.
Cooling BTU ≈ room sq ft × 20–30 (by climate zone)The AC sizing rule of thumb — hotter zones use the higher multiplier, then adjust for sun exposure, ceiling height, and occupants.
Board feet = (thickness in × width in × length ft) / 12The lumber-yard pricing unit — one board foot is a 1″ × 12″ × 12″ piece, measured on nominal dimensions.

Frequently asked questions

How accurate are these material takeoffs?

Each calculator uses the same waste-factor and overage rules a job-site estimator would apply. The defaults err on the side of slightly over-ordering (because under-ordering costs more in delivery fees and lost time than the extra material). You can adjust the waste factor on every quantity calculator.

Are the engineering calculators (HVAC, structural, electrical) code-compliant?

They use ASHRAE Manual J/D/S (HVAC), NEC current edition (electrical), and IBC/IRC current editions (structural) as the basis. They produce defensible numbers for planning and permit submission, but any project that requires a stamped drawing should be reviewed by a licensed engineer in your jurisdiction.

What's the difference between the Material Estimation guide and the calculators?

The guide explains the unit-of-measure conventions (cubic yards vs bags, board-feet vs linear-feet, squares vs square-feet) and the waste-factor framework. The calculators apply those conventions to your specific dimensions. Read the guide once; bookmark the calculators.

Do these calculators handle metric units?

Most have a unit-toggle in the input panel that switches between US customary (inches, feet, pounds, °F) and metric (cm, m, kg, °C). The structural and electrical calculators expose the underlying conversion factors so you can verify the math.

Why isn't there a permit-cost calculator for my city?

The Permit Fee Calculator handles the most common jurisdictional fee schedules (IBC valuation method, plan-review percentage, plumbing fixture unit fee). For city-specific fees, link your jurisdiction's permit office page from inside the calculator — the inputs are flexible enough to model most local schedules.

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