WHP to HP Calculator
Enter WHP or HP, then select Drive Train to calculate the missing horsepower.
Converting WHP to Engine HP:
Engine HP = WHP ÷ (1 – Drivetrain Loss%/100)
Converting Engine HP to WHP:
WHP = Engine HP × (1 – Drivetrain Loss%/100)
Typical drivetrain losses:
- Front-Wheel Drive (FWD): ~15% loss
- Rear-Wheel Drive (RWD): ~20% loss
- All-Wheel Drive (AWD): ~25% loss
These percentages can vary based on the specific vehicle, transmission type, and other factors.
What Is a WHP to HP Calculator?
A WHP to HP Calculator is a tool used to estimate a vehicle’s engine horsepower (HP) based on its wheel horsepower (WHP) and drivetrain type. The engine’s power output is typically higher than the power delivered to the wheels due to drivetrain power losses.
Understanding this calculation helps car enthusiasts, mechanics, and performance tuners gauge the true capability of their vehicle’s engine.
How to Use the WHP to HP Calculator
To calculate engine horsepower from wheel horsepower, follow these simple steps:
1. Select Calculation Type
Choose what you want to calculate:
- Engine HP from Wheel HP (Convert WHP to engine HP)
- Wheel HP from Engine HP (Convert engine HP to WHP)
2. Enter Horsepower Value
Input either the Wheel Horsepower (WHP) or Engine Horsepower (HP) depending on your selected calculation type.
3. Choose Drivetrain Type
Select the drivetrain layout of your vehicle:
- Front-Wheel Drive (FWD): Average drivetrain loss of 10-15%
- Rear-Wheel Drive (RWD): Average drivetrain loss of 15-20%
- All-Wheel Drive (AWD): Average drivetrain loss of 20-25%
4. Custom Drivetrain Loss (Optional)
If you know the exact drivetrain loss percentage of your vehicle, enter the custom value for a more accurate result.
5. Calculate
Click the Calculate button to get the estimated horsepower result.
How Does the WHP to HP Calculation Work?
Drivetrain components such as transmissions, differentials, and axles consume a portion of the engine’s power before it reaches the wheels. The WHP to HP Calculator uses the following formula:
Engine HP Formula
\[ HP = \frac{WHP}{1 – (Drivetrain Loss \% / 100)} \]Wheel HP Formula
\[ WHP = HP \times (1 – (Drivetrain Loss \% / 100)) \]Example Calculation
- Wheel Horsepower (WHP): 300 WHP
- Drivetrain Type: Rear-Wheel Drive (RWD)
- Drivetrain Loss: 17%
So, the estimated engine horsepower is approximately 361 HP.
Why Use a WHP to HP Calculator?
1. Performance Tuning
Helps performance tuners estimate the true engine output when upgrading or modifying vehicles.
2. Comparing Dyno Results
Dyno tests measure wheel horsepower, so converting to engine horsepower helps compare results with manufacturer specifications.
3. Drivetrain Efficiency Evaluation
Identify how much power is lost through the drivetrain, which can help diagnose mechanical issues or optimize performance.
4. Custom Vehicle Builds
Essential for calculating engine power in custom-built vehicles with non-standard drivetrains.
Factors Affecting Drivetrain Loss
- Transmission Type (Manual or Automatic)
- Differential Design
- Tire Type and Pressure
- Axle Configuration
- Fluid Viscosity (Transmission and Differential Oil)
Tips to Minimize Drivetrain Loss
- Regularly maintain transmission and differential fluids.
- Use lightweight drivetrain components where possible.
- Upgrade to performance-grade bearings and axles.
- Ensure proper tire pressure and alignment.
