• VinFast Battery Degradation Calculator
    Estimate VinFast EV battery degradation, remaining capacity and current driving range based on age and yearly degradation rate. Quick, free tool.
  • Tire Size Conversion Calculator
    Convert metric tire sizes (e.g. 225/45R17) to inches. Calculate overall diameter, section width, sidewall height, circumference and revs per mile.
  • Speed from Skid Mark Calculator
    Estimate a vehicle's minimum speed from skid mark length, road drag factor, and braking efficiency. Outputs mph, km/h, ft/s, and m/s instantly.
  • Gallons of Gas for Trip Calculator
    Calculate how many gallons of gas you need for a trip from distance and MPG, plus estimated fuel cost. Fast, free road-trip fuel planner.
  • Gas Mileage (MPG) Calculator
    Calculate your car's gas mileage in miles per gallon (MPG) from miles driven and gallons used. Also shows L/100km and km/L equivalents.
  • Gas Mileage / Fuel Economy Calculator
    Calculate gas mileage and fuel economy in MPG (US), MPG (Imperial), km/L and L/100km from distance and fuel used, plus trip fuel cost.
  • How Much Car Can I Afford? (Car Affordability Calculator)
    Find the max car price you can afford from a target monthly payment, loan term, APR, sales tax, down payment and trade-in. US sales-tax model.
  • Car Loan Payment Calculator
    Estimate your monthly car loan payment from price, sales tax, down payment, trade-in, term and interest rate. See total interest and financed amount.
  • Car Loan Calculator
    Calculate your car (auto) loan monthly payment, total amount paid, and total interest from the loan amount, term, and annual interest rate.
  • Horsepower to Amps Calculator
    Convert horsepower (HP) to amps for DC, single-phase, and three-phase motors. Enter voltage, efficiency, and power factor to get current draw in amps.
  • Fuel Economy Calculator
    Calculate your vehicle's fuel economy in MPG from distance driven and fuel used. Also converts to L/100km and km/L instantly.
  • Tire Manufacture Date Calculator
    Decode the 4-digit DOT tire code to find the exact week and calendar date your tire was manufactured. Works for tires made in 2000 or later.
  • Bike Chain Length Calculator
    Calculate the correct bicycle chain length from chainstay length, largest chainring and largest cog using the rigid chain length equation. Results in inches and links.
  • Reaction Time Distance Calculator
    Calculate the distance your vehicle travels during your reaction time. Enter speed (km/h, mph, m/s) and reaction time to get reaction distance.
  • Gear Ratio RPM Calculator
    Calculate output RPM from input speed and gear ratio. Enter motor/engine RPM and the gear ratio to find the resulting shaft speed instantly.
  • Speedometer Correction Calculator
    Find your true speed after changing tire size. Enter indicated speed plus old and new tire diameters to see corrected speed and speedometer error.
  • Monthly Fuel Cost Calculator
    Estimate your monthly fuel cost from miles driven, MPG, and fuel price. See gallons used and yearly spend instantly with this gas cost calculator.
  • Engine RPM from MPH Calculator
    Calculate engine RPM at any speed from your gear ratio, final drive ratio, and tire diameter. Free RPM-from-MPH calculator with worked example.
  • Fuel Economy Unit Converter (km/L ⇔ mpg ⇔ L/100km)
    Convert fuel economy between km/L, L/100km, L/km, US mpg and Imperial mpg, plus gal/100mi. Enter one value and get all eight units at once.
  • Fuel Injector Calculator
    Calculate the optimal fuel injector size for your engine with our free online calculator. Input engine displacement, cylinder count, max horsepower, and fuel pressure for accurate results. Perfect for car enthusiasts and mechanics.
  • Propeller Slip Calculator
    Calculate boat propeller slip percentage from engine RPM, prop pitch, gear ratio and actual speed. Free online prop slip calculator with theoretical speed.
  • Mean Piston Speed Calculator
    Calculate mean piston speed (MPS) from stroke and RPM. Enter stroke in mm and engine speed to get piston speed in m/s and ft/min instantly.
  • Piston Force Calculator
    Calculate piston force from pressure and bore diameter using F = P × (π/4) × D². Supports SI (Pa, m → N) and Imperial (psi, in → lbf) units.
  • Gear Ratio Calculator
    Calculate gear ratio from driver and driven gear teeth, then find output speed (RPM) and output torque for any gear pair. Fast and free.