Boost Horsepower Calculator
Estimate the horsepower gain from adding forced induction (turbo or supercharger) boost. Enter your engine's naturally aspirated horsepower and the boost pressure in PSI to see the estimated boosted horsepower.
Formula
Boosted HP = Base HP × (14.7 + Boost PSI) ÷ 14.7
- Adding boost forces more air (and fuel) into the engine, raising power roughly in proportion to absolute manifold pressure.
- The estimate scales base horsepower by (atmospheric + boost) ÷ atmospheric, using 14.7 psi for sea-level atmospheric pressure.
- It is an ideal, first-order estimate — real gains depend on intercooling, fuel, tuning, and engine limits.
- Doubling absolute pressure (about 14.7 psi of boost) roughly doubles theoretical airflow and power.
- Always confirm an engine can safely handle the target boost before relying on these numbers.
200 hp engine with 7 psi boost
Inputs
- Naturally Aspirated Horsepower: 200 hp
- Boost Pressure: 7 psi
Boosted HP = 200 × (14.7 + 7) ÷ 14.7 ≈ 295 hp, a gain of about 95 hp (48%).
Frequently asked questions
How does boost increase horsepower?
Forced induction packs more air into each cylinder, allowing more fuel to burn, which produces more power roughly in line with the pressure increase.
Why is 14.7 used in the formula?
14.7 psi is standard atmospheric pressure at sea level. Boost is added on top of it, so power scales with total absolute pressure.
Is this estimate exact?
No. It is an idealized estimate. Real-world gains depend on intercooling, fuel quality, engine tuning, and mechanical limits.
How much boost is safe?
It varies widely by engine. Stock internals often tolerate modest boost, but high boost may require forged components and careful tuning.
Does more boost always mean more power?
Up to a point. Beyond an engine's airflow, fuel, or strength limits, extra boost yields diminishing returns or causes damage.