Boost Horsepower Calculator

Estimate the horsepower gains from adding a turbocharger or supercharger.

Boost HP Calculator
HP
PSI
BOOSTED HORSEPOWER
HP

Formula

Formula
Boosted HP = NA HP × ((PSI / 14.7) + 1)
14.7 is standard atmospheric pressure. Assumes identical volumetric efficiency.

Adding 14.7 PSI of boost effectively doubles the atmosphere the engine breathes, theoretically doubling horsepower. In reality, heat and inefficiencies reduce this gain slightly.

Worked Example

Worked Example
1. Base HP: 300
2. Boost: 10 PSI
3. 300 × ((10 / 14.7) + 1) = 504 HP

This calculator provides estimates based on standard mathematical formulas. Real-world results will vary based on mechanical condition, environmental factors, and other variables.

Frequently Asked Questions

Roughly 6-7% of the engine's naturally aspirated horsepower.

Turbos are generally more efficient because they run on exhaust gas, while superchargers rob some engine power via a belt to compress the air.

As a rough rule, each additional PSI of boost adds roughly 7% over the naturally aspirated power, though this varies with engine efficiency, intercooling, and tuning.

A turbocharger is driven by exhaust gas and is more efficient but can lag; a supercharger is belt-driven for instant response but consumes engine power to run.

Compressing air heats it, and hot air is less dense. An intercooler cools the charge back down, packing more oxygen into each cylinder for more power and less knock risk.