Engine & Performance Calculators

Calculate horsepower using RPM & torque, elapsed quarter-mile time, or trap speed. Determine engine displacement, compression ratio, carburetor sizing, gear ratios, and more. All results display in both US and metric units instantly.

All Engine & Performance Calculators

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Engine Horsepower Calculator

Calculate engine horsepower using RPM & torque, quarter-mile elapsed time, or trap speed methods. Supports HP, kW, and PS conversions.

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Engine Torque Calculator

Calculate engine torque from horsepower and RPM. Convert between lb-ft, Nm, and kg-m. See the torque curve relationship.

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Engine Displacement Calculator

Calculate engine displacement (CID/cc/L) from bore, stroke, and number of cylinders. Compare common engine configurations.

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Engine Compression Ratio Calculator

Calculate engine compression ratio from swept volume and clearance volume. Understand the impact on power and fuel octane requirements.

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Carburetor CFM Calculator

Calculate the correct carburetor size in CFM for your engine using displacement, RPM, and volumetric efficiency.

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0–60 & Quarter Mile Calculator

Estimate quarter-mile elapsed time and trap speed from vehicle weight and horsepower. Calculate 0-60 mph time.

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Horsepower-to-Weight Ratio Calculator

Calculate power-to-weight ratio in HP/ton, lb/HP, and HP/liter. Compare your vehicle's performance potential against common benchmarks.

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Gear Ratio Calculator

Calculate overall gear ratio, RPM at speed, and speed at RPM from transmission gear, differential ratio, and tire size.

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Top Speed Estimator

Estimate a vehicle's theoretical top speed from horsepower, weight, drag coefficient, and frontal area.

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Dyno Correction Factor Calculator

Calculate SAE J1349, DIN 70020, and STD dyno correction factors from temperature, barometric pressure, and humidity.

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💡 Understanding Engine Performance Metrics

Engine horsepower and torque are the two fundamental measures of engine output. Horsepower measures the rate at which work is done — how quickly the engine can move a vehicle. Torque measures the rotational force — how much pulling strength the engine produces. The two are mathematically related: HP = (Torque × RPM) ÷ 5,252.

Engine displacement (measured in cubic inches, cubic centimeters, or liters) describes the total volume swept by all pistons in the engine. Larger displacement generally means more power, but modern turbocharging allows smaller engines to match or exceed the output of larger naturally aspirated motors. Compression ratio affects both power output and the octane fuel required.

Pro tip: Use the Quarter Mile Calculator to estimate your vehicle's ET and trap speed from HP and weight — these are the two most popular drag strip metrics.