Calculate torque from horsepower, kilowatts, RPM, efficiency, and speed inputs. Switch units with simple controls. View instant summaries, graphs, tables, exports, and use notes.
| Case | Power | RPM | Efficiency | Gear Ratio | Final Drive | Wheel Radius | Torque Rise |
|---|---|---|---|---|---|---|---|
| Compact Petrol | 140 hp | 4200 | 90% | 3.20 | 3.90 | 0.31 m | 8% |
| Diesel Utility | 110 kW | 2800 | 88% | 3.80 | 4.10 | 0.35 m | 15% |
| Performance Setup | 220 hp | 6000 | 92% | 2.90 | 3.70 | 0.33 m | 5% |
Engine torque links power and rotational speed. The base relation is torque equals power divided by angular speed.
Angular speed: ω = 2π × RPM / 60
Base engine torque: T = P / ω
Shortcut with kilowatts: T(N·m) = 9549.2966 × kW / RPM
Adjusted engine torque: Adjusted Torque = Base Torque × (1 + Torque Rise / 100)
Wheel torque: Wheel Torque = Adjusted Torque × Gear Ratio × Final Drive Ratio × Efficiency
Tractive force: Force = Wheel Torque / Wheel Radius
This calculator also converts N·m into lb-ft and kgf-m for quick comparison.
Enter the engine power first. Choose the correct unit. Then enter engine speed in RPM. Add drivetrain efficiency to reflect real losses. Enter the active gear ratio and final drive ratio. Add wheel radius if you want wheel torque and tractive force outputs. Use torque rise when you want a boosted torque estimate. Pick the output torque unit. Press the calculate button. The result appears above this form. You will see a summary table, export buttons, and a graph. Use the CSV option for spreadsheets. Use the PDF option for reports or client sharing.
Engine torque is the twisting force produced at the crankshaft. It tells you how strongly the engine can rotate a load. Higher torque usually improves pulling power, launch feel, and low speed response. It is different from power, but both values are connected.
Torque changes with speed. For the same power, torque becomes lower as RPM rises. That is why an engine can feel strong at one speed and softer at another. This calculator helps you estimate torque from known power and RPM values with fast unit conversion.
Not all engine output reaches the wheels. Some energy is lost through the gearbox, bearings, driveshaft, differential, and tires. Drivetrain efficiency lets you estimate usable wheel torque instead of ideal crank torque. This creates a more realistic result for engineering review and vehicle analysis.
Gear multiplication increases torque at the wheels. A larger gear ratio or final drive ratio raises wheel torque. It also changes vehicle speed for the same RPM. This matters when comparing first gear pull, towing response, hill climbing, or launch setup performance.
The result section shows input power in common units, engine speed, angular speed, base torque, adjusted torque, wheel torque, and tractive force. The graph shows how torque changes across RPM when power stays fixed. This supports quick scenario testing and engineering comparisons.
You can use it for engine matching, drivetrain studies, training, workshop estimation, and academic examples. It is useful for petrol, diesel, electric conversion projects, racing analysis, and general mechanical design work. Always compare the estimate with dyno data when exact validation is required.
Engine torque is rotational force at the crankshaft. It shows how strongly the engine can twist and move a load at a given speed.
No. Torque is twisting force. Horsepower is the rate of doing work. They are connected through RPM, but they are not identical values.
RPM is required because torque depends on rotational speed. The same power value produces different torque values at different engine speeds.
It reduces the ideal torque that reaches the wheels. This makes wheel torque and tractive force estimates more realistic for real vehicles.
These ratios multiply engine torque. They help estimate wheel torque for a selected driving gear rather than crankshaft torque alone.
Torque rise is an optional percentage increase above base torque. It can represent a stronger load response or a more conservative performance estimate.
Yes. The calculator accepts horsepower, kilowatts, and watts. It converts the input internally before calculating engine torque.
No. They are engineering estimates based on the values you enter. Use measured dyno or test data for final verification.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.