PSI to HP Calculator
Convert hydraulic pressure (PSI) and flow (GPM) into horsepower — and see why PSI alone can't become HP.
PSI is pressure, not power — a sealed cylinder can hold 3,000 PSI forever while doing zero work. Power appears only when pressurized fluid flows. That's why converting PSI to horsepower always needs the flow rate in gallons per minute.
PSI to HP Formula
Why You Can't Convert PSI Alone
Pressure is force per area; power is work per time. The same 5 HP can appear as 3,430 PSI at 2.5 GPM (a log splitter) or 429 PSI at 20 GPM (a high-flow circuit). If someone quotes "PSI to HP" without flow, they're implicitly assuming a flow rate — always find out which one. The reverse question ("1 HP = how many PSI?") has no fixed answer for the same reason.
Hydraulic HP at Common Pressure/Flow Combinations
| PSI \ GPM | 5 GPM | 10 GPM | 15 GPM | 20 GPM |
|---|---|---|---|---|
| 1,000 | 2.9 | 5.8 | 8.8 | 11.7 |
| 1,500 | 4.4 | 8.8 | 13.1 | 17.5 |
| 2,000 | 5.8 | 11.7 | 17.5 | 23.3 |
| 2,500 | 7.3 | 14.6 | 21.9 | 29.2 |
| 3,000 | 8.8 | 17.5 | 26.3 | 35.0 |
Worked Example
Frequently Asked Questions
No — pressure alone isn't power. You need the flow rate too: HP = PSI × GPM ÷ 1,714.
There's no fixed answer — it depends on flow. 1 HP supports 1,714 PSI at 1 GPM, 343 PSI at 5 GPM, or 171 PSI at 10 GPM.
No — it gives fluid (output) power. Divide by pump efficiency (typically 0.80–0.90) to size the motor or engine driving the pump.
One gallon is 231 in³ (19.25 board-feet of work per PSI per minute). Converting gallon-PSI/min into 33,000 ft-lb/min (1 HP) yields the constant 1,714.