Automotive calculators
Compare ownership costs, fuel and EV charging, tires, towing, maintenance, and performance.
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Engine Tuning · 9
Fuel & Energy · 7
Ownership Costs · 14
Performance · 24
Tires & Wheels · 9
What the car actually costs each month.
Payment, insurance, fuel, maintenance, depreciation — stack them up, get a cost per mile, and see whether owning still beats the alternatives.
True Monthly Cost of Ownership
Drag the four big line items — payment, insurance, fuel, maintenance — and see the all-in monthly total plus your computed cost per mile.
Car Lease vs Buy
Line up lease payments against loan payments plus equity — see which comes out ahead over the term you actually keep cars.
Lease vs Buytotal-cost gap over the termGas, electrons, and the price of a mile.
MPG math, monthly fuel budgets, charging cost per mile, and whether the EV really pencils out against the pump.
The EPA energy equivalence behind every MPGe and cost-per-mile figure on this shelf.
Monthly Fuel Cost Estimator
Drag miles per month, your MPG, and the pump price — see the monthly fuel bill and what a year of driving costs.
Gas vs Electric
Total cost of ownership head-to-head — purchase price, fuel vs electricity, maintenance, and the break-even year.
TCO head-to-headbreak-even year & lifetime gapTires, torque, and stopping power.
Tire-size fitment and speedometer error, 0-60 estimates from power and weight, torque conversion, and braking distance by road condition.
Tire Size Comparator
Dial in your stock size and the size you want — see the overall-diameter change and how far off your speedometer will read.
0-60 MPH Estimator
Estimate 0-60 time from horsepower, curb weight, and drivetrain — see how a tune or weight cut moves the number.
HP + weight → 0-60power-to-weight estimateBoost, cooling, and the parts that keep it all fed.
Sizing math for turbo builds — intercooler core volume, fuel pump flow, and injector sizing — plus 2-stroke premix ratios, with more engine-tuning tools on the way.
Intercooler Sizing Calculator
Estimate the minimum intercooler core volume for a target horsepower and boost level, and compare air-to-air against air-to-water.
HP + boost → core volumein³ needed for your targetFuel Pump Sizing Calculator
Find the minimum LPH fuel pump flow rate for a target horsepower, with a safety margin for boosted or E85 builds.
HP + BSFC → LPHminimum pump flow neededPressure, fitment, and everything that touches the road.
How temperature shifts your tire pressure day to day, plus decoding a sidewall size code into overall diameter, circumference, and revs per mile.
Tire Pressure by Temperature Calculator
See how much your tire pressure shifts with the outside temperature, using the ~1 PSI per 10°F rule, plus add-air guidance.
ΔTemp → ΔPSIexpected pressure at any tempTire Diameter Calculator
Enter a sidewall size code like 225/60R16 and get overall diameter, circumference, and revolutions per mile instantly.
225/60R16 → 26.6 inoverall diameterHow much you can safely hitch up and haul.
Your maximum safe towing capacity from GCWR, curb weight, and passenger/cargo load, payload capacity from GVWR minus curb weight, and a full GVWR/GCWR weight-margin check, with more towing-and-hauling tools on the way.
Towing Capacity Calculator
Calculate your vehicle's maximum safe towing capacity from its GCWR, curb weight, and passenger/cargo load, and check a trailer's weight against it.
GCWR − loaded weightmax towing capacityPayload Capacity Calculator
Find your maximum payload from GVWR and curb weight, then see what's left once passengers, cargo, and tongue weight are loaded.
GVWR − curb → max payloadremaining capacity once loadedBigger than one calculator? Follow the flow.
Multi-step paths that string the right automotive tools together in the order most people actually use them — with your numbers carried from step to step.
The automotive vocabulary, decoded.
Every definition links to the calculator that puts the term to work. Browse the full glossary →
MPG = miles driven ÷ gallons usedThe standard US fuel-economy measure — divide distance traveled by fuel consumed.Overall ratio = gear ratio × final drive ratioMultiply the transmission's gear ratio by the differential's final drive ratio to get the total reduction from engine to wheels.Cost/mile = (fuel + maintenance + depreciation + insurance) ÷ miles drivenEvery real ownership cost, spread across the miles actually driven — the number that makes vehicles genuinely comparable.Frequently asked questions
How do I calculate my real cost per mile?
Add every monthly cost of the car — payment, insurance, fuel or charging, maintenance, registration — and divide by the miles you drive per month. Most owners land between $0.50 and $0.90 per mile; the AAA average for a new vehicle is roughly $0.80. The ownership widget above does the quick version, and the Car Ownership vs Rideshare calculator runs the full comparison.
Is leasing cheaper than buying?
Over a single 3-year term, leasing often has lower monthly payments — but you build no equity. Buying costs more per month yet leaves you with a car worth thousands at the end. The Lease vs Buy calculator compares total cost over the term including residual value, so the answer depends on how long you keep cars and how many miles you drive.
Do bigger tires really affect my speedometer?
Yes. Your speedometer counts wheel revolutions calibrated to the stock tire diameter. A taller tire covers more ground per revolution, so the speedometer reads low — at an indicated 60 mph you may actually be doing 62 or more. Most cars tolerate about ±3% diameter change; beyond that, recalibration or a different size is recommended.
Is an EV actually cheaper per mile than gas?
Usually, but it depends on your electricity rate and local gas prices. Home charging at a typical residential rate works out to roughly a third of the per-mile fuel cost of a comparable gas car; DC fast charging narrows the gap considerably. The EV Charging Cost and Gas vs Electric calculators run the math with your own rates.
15 categories, one search box, zero signups. If it has a number, we calculate it.
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