Estimate wheel power or engine power with a supplied drivetrain-loss percentage, or calculate loss from both powers. Supports kW, mechanical hp and metric PS. FWD/RWD/AWD preset percentages and article tables are illustrative scenarios, not universal drivetrain ratings.
| Engine hp to Wheel hp | Wheel hp to Engine hp |
|---|---|
| 100 hp = 85 hp | 120 hp = 141.2 hp |
| 150 hp = 127.5 hp | 170 hp = 200 hp |
| 200 hp = 170 hp | 225 hp = 264.7 hp |
| 250 hp = 212.5 hp | 275 hp = 323.5 hp |
| 300 hp = 255 hp | 325 hp = 382.4 hp |
| 350 hp = 297.5 hp | 375 hp = 441.2 hp |
| 400 hp = 340 hp | 425 hp = 500 hp |
| 450 hp = 382.5 hp | 475 hp = 558.8 hp |
| 500 hp = 425 hp | 550 hp = 647.1 hp |
| 600 hp = 510 hp | 650 hp = 764.7 hp |
| 700 hp = 595 hp | 750 hp = 882.4 hp |
| 800 hp = 680 hp | 850 hp = 1,000 hp |
| Formulas: Wheel = Engine × (1 − Loss) and Engine = Wheel ÷ (1 − Loss). (Loss = 0.15.) | |
| Engine hp to Wheel hp | Wheel hp to Engine hp |
|---|---|
| 200 hp = 160 hp | 180 hp = 225 hp |
| 300 hp = 240 hp | 260 hp = 325 hp |
| 400 hp = 320 hp | 340 hp = 425 hp |
| 500 hp = 400 hp | 420 hp = 525 hp |
| 600 hp = 480 hp | 520 hp = 650 hp |
| 700 hp = 560 hp | 620 hp = 775 hp |
| 800 hp = 640 hp | 720 hp = 900 hp |
| 1,000 hp = 800 hp | 900 hp = 1,125 hp |
| Formulas: Wheel = Engine × (1 − Loss) and Engine = Wheel ÷ (1 − Loss). (Loss = 0.20.) | |
Engine kW to Wheel kW Formula
The following formula is used to calculate the kW at the wheel given the engine kW.
- Where W(kW) is the wheel kilowatts (kW)
- E(kW) is the engine kilowatts (kW)
- DTL is the drive train loss
- 10% example: use DTL = 0.10, not 10
- 15% example: use DTL = 0.15
- 20% example: use DTL = 0.20. These examples are not universal drivetrain rates.
To calculate wheel kW, multiply engine kW by (1 − DTL), where DTL is the fraction of engine power lost. Reverse engine power = wheel power / (1 − DTL). Any additional loss entered in the calculator adds percentage points of engine power and must not duplicate loss already included in the base percentage.
What is Wheel kW?
Definition:
Wheel kW is power delivered at the wheels after drivetrain losses. It applies to combustion-engine and electric vehicles. A constant-percentage calculation is an estimate; it does not replace consistent crankshaft and chassis-dynamometer measurements.
How to calculate wheel kW?
Example Problem:
The following example problem outlines how to calculate wheel kW from engine kW.
First, determine the power output of the engine in kilowatts. For this example, the engine outputs 1000 kW.
Next, determine the losses by the drivetrain. In this example, the electric vehicle is all-wheel drive and has a 20% loss.
Finally, calculate the wheel kW using the formula above:
W(kW) = E(kW) – E(kW)*DTL
W(kW) = 1000 – 1000*.20
W(kW) = 800 kW
