GPH to PSI Converter
Gallons per hour is a slow flow. Change it to gallons per minute first, then use the horsepower sum.
Quick answer: Divide the gph by 60 to get gpm, then use hp × 1,714 ÷ gpm. The answer is the pressure in psi. For example, 600 gph, 5 hp is 857 psi, 300 gph, 2 hp is 685.6 psi and 1,800 gph, 10 hp is 571.33 psi.
The gph to psi formula
One hour is 60 minutes, so gph divided by 60 is gpm.
Hydraulic horsepower is gpm times psi divided by 1,714 (Engineers Edge: Hydraulic Pump Horsepower Equation). So psi is hp × 1,714 ÷ gpm.
Take 600 gph, 5 hp. 5 × 1714 × 60 ÷ 600 gives 857 psi.
Take 300 gph, 2 hp. 2 × 1714 × 60 ÷ 300 gives 685.6 psi.
Slow flow and power to pressure
A pump turns power into flow and pressure.
For a set power, more flow means less pressure.
Gph is a slow way to give flow, so change it to gpm first.
How to convert gph to psi step by step
- Write down the flow in gph and the power in horsepower.
- Divide the gph by 60. That gives gpm.
- Multiply the horsepower by 1,714, then divide by the gpm.
- The answer is the pressure in psi.
Example 1: 600 gph, 5 hp
- Start with 600 gph, 5 hp.
- 5 × 1714 × 60 ÷ 600 = 857.
- The pressure is 857 psi.
600 gph, 5 hp = 857 psi
Example 2: 300 gph, 2 hp
- Start with 300 gph, 2 hp.
- 2 × 1714 × 60 ÷ 300 = 685.6.
- The pressure is 685.6 psi.
300 gph, 2 hp = 685.6 psi
Example 3: 1,800 gph, 10 hp
- Start with 1,800 gph, 10 hp.
- 10 × 1714 × 60 ÷ 1,800 = 571.33.
- The pressure is 571.33 psi.
1,800 gph, 10 hp = 571.33 psi
The sum treats the pump as perfect. Real pumps lose some power, so the true pressure is a little lower.
gph to psi conversion table
| Flow and power | Pressure (psi) | Pressure (bar) |
|---|---|---|
| 60 gph, 1 hp | 1,714 psi | 118.18 bar |
| 300 gph, 2 hp | 685.6 psi | 47.27 bar |
| 600 gph, 2 hp | 342.8 psi | 23.635 bar |
| 600 gph, 5 hp | 857 psi | 59.088 bar |
| 900 gph, 5 hp | 571.33 psi | 39.392 bar |
| 1,200 gph, 10 hp | 857 psi | 59.088 bar |
| 1,800 gph, 10 hp | 571.33 psi | 39.392 bar |
| 2,400 gph, 15 hp | 642.75 psi | 44.316 bar |
The highlighted row is the default of the calculator. The last column gives bar.
A quick mental shortcut for gph to psi
Divide the gph by 60 to get gpm. Then multiply the horsepower by 1,700 and divide by the gpm.
So 5 hp at 600 gph is 10 gpm, which is about 850 psi.
What gph measures
A gph is one US gallon of flow each hour. It is a slow flow.
Small pumps and dosing sheets use it.
What psi measures
A psi is one pound-force pressing on one square inch (Wikipedia: Pound per square inch).
US tyre gauges, tanks and hoses use it.
A small pump
A pump with 5 hp at 600 gph is 10 gpm. It can reach about 857 psi.
That is 59.09 bar.
A slow flow case
A pump with 2 hp at 300 gph is 5 gpm. It can reach about 685.6 psi.
That is 47.27 bar.
A big flow case
A pump with 10 hp at 1,800 gph is 30 gpm. It can reach about 571.3 psi.
That is 39.39 bar.
Losses are ignored
The sum treats the pump as perfect. Real pumps lose some power as heat and friction.
So the real pressure is a little less than the answer.
Why times 60
There are 60 minutes in an hour, so gpm is gph ÷ 60.
Dividing by gpm is the same as multiplying by 60 over the gph.
Going the other way
To go back, multiply the gph by the psi, divide by 60, then divide by 1,714. The answer is the horsepower.
So 857 psi at 600 gph is 5 hp.
Check your answer
Your psi should fall when the flow rises, for the same power.
Reverse the steps and you should get your first number.
Quick conversion answers
| Conversion | Result |
|---|---|
| 300 gph, 2 hp | 685.6 psi |
| 600 gph, 5 hp | 857 psi |
| 900 gph, 5 hp | 571.33 psi |
| 1,200 gph, 10 hp | 857 psi |
| 1,800 gph, 10 hp | 571.33 psi |
| 2,400 gph, 15 hp | 642.75 psi |
Where this conversion is used
Shop staff size small pumps.
Technicians check hydraulic limits.
Students solve power sums.
Common mistakes to avoid
- Mixing up gpm and gph. One gpm is 60 gph.
- Forgetting losses. The sum is for an ideal pump. Real pumps give a little less.
- Using the wrong power. Use the power at the pump shaft, not the motor label.
- Rounding too early. The answer for 300 gph, 2 hp is 685.6 psi. Cut it to 690 psi and you are off by about 0.6 percent, and the gap grows if you reuse it.
Related converters
A dosing pump
A pump with 1 hp at 60 gph is 1 gpm. It can reach about 1,714 psi.
That is 118.2 bar.
A medium pump
A pump with 15 hp at 2,400 gph is 40 gpm. It can reach about 642.8 psi.
That is 44.32 bar.
Frequently asked questions
How do I find psi from gph?
Divide the gph by 60 to get gpm. Then multiply the horsepower by 1,714 and divide by the gpm.
How many psi can 5 hp make at 600 gph?
About 857 psi.
How many gpm is 600 gph?
10 gpm.
Why is the answer a limit?
Real pumps lose some power, so they give a little less.
What does 1,714 mean?
It joins gpm, psi and horsepower in one sum.
How many bar is 857 psi?
About 59.09 bar.
Sources
- Engineers Edge: Hydraulic Pump Horsepower Equation (engineersedge.com)
- Wikipedia: Pound per square inch (en.wikipedia.org)
- Wikipedia: Bar (unit) (en.wikipedia.org)
