Pick your Calculation Mode, then enter your Engine Speed (RPM) along with either Horsepower or Torque — the calculator works out the missing value and plots your full torque curve, returning Peak Torque, Peak Power, and your Torque/Power Ratio.
Calculated Torque
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Calculated Power
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Peak Torque
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Peak Power
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Torque/Power Ratio
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Torque is calculated using the formula: Torque = (Horsepower × 5,252) ÷ RPM. This conversion factor 5,252 comes from the relationship between foot-pounds, horsepower, and rotational speed in the imperial system.
Torque measures the rotational force an engine produces, while horsepower measures the rate at which work is done. Torque determines acceleration feel, while horsepower determines top speed capability.
Peak torque typically occurs between 2,500-4,500 RPM in most engines. Lower RPM peak torque provides better low-end pulling power, while higher RPM peak torque favors high-speed performance.
The torque curve shows how much rotational force your engine produces across its RPM range. A flat, broad curve indicates good drivability, while a peaked curve suggests the engine is optimized for a specific RPM range.
Horsepower is torque multiplied by RPM, so even as torque decreases at higher RPM, horsepower can still increase until the torque drop-off becomes too steep. This typically happens at much higher RPM than peak torque.
Factors include engine displacement, compression ratio, camshaft profile, intake and exhaust design, turbocharging/supercharging, and fuel delivery system. Each component influences where and how much torque is produced.
Calculated curves provide good estimates but actual dyno testing is more accurate. Real engines have variations due to individual tolerances, tuning, condition, and environmental factors that calculations cannot account for.