Free Automotive Calculators
Instant answers for your vehicle questions. All tools run in your browser — no signup, no waiting.
Tire Calculators
Tire Size Calculator
Compare two tire sizes side by side. See diameter difference, width change, sidewall height, circumference, revs per mile, and speedometer error.
Speedometer Correction Calculator
Calculate actual speed vs displayed speed after changing tire sizes. See error at every speed from 30 to 80 mph.
Tire Pressure Calculator
Find the correct tire pressure adjusted for temperature changes and load level. See how weather affects your PSI and TPMS threshold.
Fuel & Economy Calculators
MPG Calculator
Calculate your vehicle's miles per gallon from miles driven and gallons used. Includes cost per mile and L/100km conversion.
Fuel Cost Calculator
Estimate fuel cost for any trip. Enter distance, vehicle MPG, and gas price. Includes round-trip toggle and MPG comparison table.
Road Trip Gas Cost Calculator
Calculate road trip fuel cost, split between passengers, and estimate drive time. Includes round-trip toggle and cost-per-mile breakdown.
Towing Calculators
Towing Capacity Calculator
Calculate remaining payload and max trailer weight. Includes tongue weight check and safety indicators.
Trailer Tongue Weight Calculator
Calculate the correct tongue weight for your trailer using the 10-15% rule. Check if your actual tongue weight is safe and within hitch limits.
Engine & Drivetrain Calculators
Gear Ratio Calculator
Calculate axle gear ratio from ring and pinion teeth. See RPM at any speed, effective ratio with tire size, and compare common ratios.
Engine Displacement Calculator
Calculate engine displacement from bore, stroke, and cylinder count. Results in cubic inches, liters, and cc with bore/stroke analysis.
Engine Horsepower Calculator
Estimate engine horsepower from quarter mile time, trap speed, or dyno wheel HP. Includes drivetrain loss calculator and HP tables.
EV Calculators
EV Range Calculator
Estimate real-world EV range adjusted for temperature, driving style, and efficiency. Includes charging cost and range comparison for 10 popular EVs.
EV Charging Cost Calculator
Calculate EV charging cost and time for Level 1, Level 2, and DC fast charging. Compare home vs public charging costs.
Maintenance Calculators
Coolant Mix Calculator
Calculate how much coolant and water to drain and add for any mix ratio. Includes freeze/boil protection chart and coolant type guide.
Oil Change Calculator
Find oil capacity by vehicle type, track oil change intervals, and calculate DIY oil change cost. Includes oil life tracker.
Brake Pad Life Calculator
Estimate brake pad lifespan from driving style, road conditions, and annual mileage. Includes replacement cost and wear tracker.
Battery Life Calculator
Estimate car battery lifespan based on climate, driving patterns, and electrical load. Track battery age and plan replacement.
Wiper Blade Size Calculator
Find the correct wiper blade size for your vehicle type. Compare conventional, beam, hybrid, and silicone wipers with price data.