ReckonBoxAuto calculators and tools
Financing & leasing
Auto Loan Calculator
Estimate your car payment with sales tax, trade-in, and fees, and see the tax your trade-in saves in the states that allow it.
Auto Lease Calculator
Estimate a car lease payment from the price, residual, and money factor, split into depreciation and rent charge, with the money factor shown as its real APR.
Cash Back vs Low Interest Calculator
Price a manufacturer rebate against a promotional low APR side by side, since you usually take one but not both, and see which costs less.
Fuel & economy
Fuel Cost Calculator
Work out the gas cost of a trip from the distance, your MPG, and the price per gallon, with the cost per mile for comparing trips or cars.
Gas Mileage Calculator
Work out your real fuel economy from the miles driven and gallons used, shown in US MPG, Imperial MPG, km per liter, and L per 100 km at once.
Mileage Reimbursement Calculator
Work out mileage reimbursement at the current IRS standard rate, with the mid-2026 business rate change built in and a custom rate for employer plans.
Performance & specs
Tire Size Calculator
Compare two tire sizes for diameter and revolutions per mile, and see how much a size change throws off your speedometer.
Horsepower Calculator
Estimate horsepower from a quarter-mile trap speed and vehicle weight using the Hale drag-strip formula, with the wheel and crank figures both shown.
Engine Horsepower Calculator
Convert engine torque and RPM into horsepower with the HP equals torque times RPM over 5252 identity, and see why every dyno chart crosses at 5252 RPM.