Calculator Directory
Automotive Calculators
Plan driving costs and vehicle-related decisions with transparent formulas and adjustable real-world inputs.
Fuel Cost Calculator Estimate gallons, fuel cost, trip fees, and cost per mile.
MPG Calculator Calculate fuel economy, L/100 km, and optional fuel cost per mile.
Driving Time Calculator Estimate driving duration and planned stop time.
Tire Size Calculator Estimate tire diameter, circumference, sidewall, and revolutions per mile.
Cost Per Mile Calculator Combine fuel and ownership expenses into a per-mile estimate.
Fuel Range Calculator Estimate driving range from available fuel, observed fuel economy, and a chosen reserve.
Engine Displacement Calculator Calculate total engine displacement in cubic centimetres, litres, and cubic inches from bore, stroke, and cylinder count.
Piston Speed Calculator Calculate mean piston speed in metres per second and feet per minute from stroke and engine RPM.
Gear Ratio Calculator Calculate a simple driver-to-driven gear ratio, output speed, and output torque under an entered efficiency.
Engine RPM at Speed Calculator Estimate engine speed from road speed, tire diameter, transmission ratio, and final-drive ratio.
Vehicle Speed from RPM Calculator Estimate road speed from engine rpm, tire diameter, transmission gear ratio, and final drive.
Power-to-Weight Ratio Calculator Compare vehicle power with weight in horsepower per US ton, watts per kilogram, and kilograms per kilowatt.
Engine Compression Ratio Calculator Calculate static geometric compression ratio from cylinder bore, stroke, clearance volume, gasket, deck, and piston volume.
Brake Mean Effective Pressure Calculator Estimate four-stroke brake mean effective pressure from engine torque and total displacement.
Wheel Offset Calculator Calculate wheel offset from total wheel width and the hub-mounting surface position measured from the inner edge.
Wheel Backspacing Calculator Estimate backspacing from overall wheel width and offset, or inspect the resulting inner mounting distance.
EV Charging Cost Calculator Estimate wall energy and charging cost from battery energy added, charger efficiency, and electricity price.
EV Charging Time Calculator Estimate charging time from usable battery capacity, starting and target state of charge, charger power, and charging efficiency.
EV Trip Cost Calculator Estimate EV trip energy, charging losses, and electricity cost from distance and observed efficiency.
Vehicle Payload Capacity Calculator Compare occupants, cargo, accessories, and trailer tongue weight with an entered vehicle payload rating.
Two-Stroke Oil Mix Calculator Calculate two-stroke oil quantity for a gasoline volume and manufacturer-specified fuel-to-oil ratio.
Windshield Washer Fluid Mix Calculator Split a desired batch volume into washer-fluid concentrate and water from a product’s stated parts ratio.
Choose the right calculator
Start with your own distance, recent fuel economy, and local pump price. Vehicle ratings are useful baselines, but real-world driving conditions can change the result.
How these calculators are checked
Each tool shows its formula, assumptions, worked example, and limitations. We test default values, decimals, zero and invalid inputs, unit conversions, and rounding behavior. Learn more on How Our Calculators Work .
Important: Automotive calculators are planning tools. They do not replace manufacturer specifications, mechanical inspection, safety instructions, or professional diagnosis.
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Reference and review
This category and its linked calculators were reviewed by the DIY Cost Tools editorial team on October 4, 2026. Additional tools will be added without changing the category URL.