Engine Build HP Calculator
Estimate horsepower from engine displacement and a power-per-litre target.
When planning an engine build, specific output — horsepower per litre — is a quick way to estimate total power from displacement. This calculator multiplies the two to project your build's output.
Engine Build HP Formula
Specific output reflects how hard an engine works. A mild naturally aspirated street engine makes 60–90 HP/L, a high-revving NA performance engine 100–130 HP/L, and turbocharged builds can exceed 150–200 HP/L. Pick the figure that matches your build's tune and induction.
How to Use This Calculator
- Enter displacement in litres.
- Set specific output (HP per litre) for your build type.
- Read the estimated horsepower.
Worked Example
Frequently Asked Questions
Multiply displacement in litres by the specific output (horsepower per litre) you expect from your build's tune and induction.
Mild naturally aspirated engines make 60–90 HP/L, high-performance NA engines 100–130 HP/L, and turbocharged builds 150–200+ HP/L.
Yes — turbo and supercharged engines achieve far higher specific output, so use a higher HP/L figure for boosted builds.
It's a planning estimate. Real output depends on cam, heads, compression, fuel, and tune, so verify on a dyno.
Use bore, stroke, and cylinder count in our engine displacement calculator, which returns litres, cc, and cubic inches.