ALL CALCULATORS

Horsepower Calculator

Crank HP from torque & RPM, or from quarter-mile times.

Torque Calculator

Convert between torque, horsepower, and engine RPM.

Compression Ratio Calculator

Static CR from bore, stroke, dome, deck, and gasket.

Engine Displacement Calculator

CI and liters from bore, stroke, and cylinder count.

Piston-to-Valve Clearance Calculator

Deck, gasket, pocket, and lift worksheet.

Carburetor CFM Calculator

CFM from CID, RPM, and volumetric efficiency.

Exhaust Pipe Diameter Calculator

Primary tube and main pipe size from torque RPM.

Volumetric Efficiency Calculator

VE from CFM or MAF, CID, and RPM.

Performance

3 calculators

Performance

Quarter Mile Calculator

Predict ET and trap speed from horsepower and weight.

Performance

0-60 MPH Calculator

Estimate 0-60 acceleration from power and weight.

Performance

Brake Bias Calculator

Static front/rear bias and stopping distance.

Drivetrain

4 calculators

Gear Ratio Calculator

Final drive, RPM at speed, and ideal axle ratio.

Tire Size Calculator

Compare diameter, speedometer error, and RPM change.

Wheel Offset & Fitment Calculator

Inboard vs outboard clearance change in mm.

Speedometer Correction Calculator

Error after gear swap or tire change.

Fuel

4 calculators

MPG Calculator

Real-world fuel economy from miles and gallons.

Fuel Cost Calculator

Trip cost from distance, MPG, and gas price.

Crude Oil to Gas Price Calculator

Barrel oil cost per gallon and pump price estimates.

Gas Guzzler Tax Calculator

Federal tax from EPA combined MPG (IRS table).

Tuning

3 calculators

Tuning

Injector Duty Cycle Calculator

Can your injectors handle target HP?

Tuning

Boost & Compression Calculator

Effective compression at any boost pressure.

Tuning

Injector Sizing Calculator

Required cc/min from HP target and BSFC.

Towing

1 calculator

Towing

Towing Capacity Calculator

GCWR, payload, and tongue weight headroom.

Financial

13 calculators

Auto Loan Calculator

Monthly payment, interest paid, and amortization.

Lease Calculator

Monthly lease payment from money factor and residual.

How Much Car Can I Afford Calculator

Max vehicle price from income or target payment.

Car Loan Payoff Calculator

Extra payments, interest saved, and payoff timeline.

Rebate vs. Low Interest Calculator

Cash back vs. 0% APR — which deal costs less?

Auto Loan Amortization Calculator

Month-by-month principal vs. interest breakdown.

Car Trade-In Equity Calculator

Positive or negative equity on your next loan.

Auto Loan Refinance Calculator

Payment savings, break-even on fees, interest comparison.

Buy vs Lease Calculator

Total cost to buy vs lease over the same term.

Out-the-Door Price Calculator

Sales tax, fees, trade — cash due at signing.

All-In Car Budget Calculator

Payment room after insurance, fuel, and maintenance.

Biweekly Car Payment Calculator

Biweekly vs monthly payoff and interest saved.