Boost Horsepower Calculator
Estimate the horsepower gain from boost pressure or work backwards to find the boost needed for a target output.
The calculator uses a pressure-ratio model with an efficiency factor so you can compare setups without guessing.
Result
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Run the calculation to see the boost estimate.
Quick Answer
Use the base horsepower, boost pressure, and efficiency factor to estimate boosted output, or reverse the equation to estimate required boost.
How to Use It
- Choose whether you want boosted horsepower or boost pressure.
- Enter the base horsepower and either boost or target power.
- Set the pressure unit and efficiency factor.
- Click Calculate and review the gain estimate.
Formula
Boosted horsepower = base horsepower x (1 + boost pressure / atmospheric pressure) x efficiency
Required boost = atmospheric pressure x ((target horsepower / (base horsepower x efficiency)) - 1)
Worked Examples
Example 1: 300 hp with 8 psi boost and 0.88 efficiency gives about 407.5 hp.
Example 2: 250 hp targeting 400 hp at the same efficiency needs about 12.0 psi.
Example 3: Switching from psi to bar changes the input scale but not the pressure-ratio idea.
How to Interpret Your Results
| Output | Meaning | Action |
|---|---|---|
| Higher boosted hp | Estimated power after boost. | Compare against drivetrain and engine limits. |
| Higher required boost | More pressure is needed to hit the target. | Check compressor and fueling capability. |
| Low efficiency factor | Real-world losses are reducing the estimate. | Use a more conservative setup. |
Frequently Asked Questions
Related Calculators
References
- OmniCalculator reference page
- The calculator uses pressure ratio and efficiency to approximate boosted output.
- Last reviewed: March 2026.