To convert US gallons per hour to cubic feet per second, multiply by 3.713348766e-05. That factor is the whole relationship: both units measure volumetric flow, so the conversion is a proportion with no offset and no substance-specific constant.
Used for fuel burn and small pumps. The cusec — how American river gauges and water rights report flow.
Standard versus actual volume. Gas flow in CFM depends on pressure and temperature, which is why compressor ratings say SCFM and specify the reference conditions. Converting the number is exact; comparing two ratings measured at different conditions is not. Two tables follow: rounded steps for quick lookup, and a set of real reference quantities converted into cubic feet per second, which is usually more useful than the bare number.
The formula
US gallons per hour- The amount you are converting, in US gallons per hour
3.71334876563e-05- The exact number of cubic feet per second in one US gallon per hour
cubic feet per second- The converted result
How it works, step by step
- Enter the value in US gallons per hour.
- It is multiplied by 3.71334876563e-05, the exact factor between the two units.
- The answer is shown in cubic feet per second, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
A bathroom tap: 95.1 GPH in cubic feet per second
A bathroom tap comes to about 95.1 GPH. Multiplying by the factor: 95.1 × 3.71335e-05 = 0.00353139 cfs. Dividing the answer back by 3.71335e-05 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
A dripping tap: 0.0951 GPH in cubic feet per second
At 0.0951 GPH (a dripping tap), the same quantity in cubic feet per second is 0.0951 × 3.71335e-05 = 3.53139e-06 cfs. One US gallon per hour is 3.71335e-05 cubic feet per second, so the numbers shrink as expected.
How to read your score
Frequently asked questions
How many cubic feet per second are in one US gallon per hour?
Exactly 3.71334876563e-05. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert US gallons per hour to cubic feet per second?
cubic feet per second = US gallons per hour × 3.71334876563e-05. Reversed, US gallons per hour = cubic feet per second ÷ 3.71334876563e-05, which is the same as multiplying by 26,929.8701284.
Which is the bigger unit, the US gallon per hour or the cubic foot per second?
The cubic foot per second. One US gallon per hour is only 3.71335e-05 of a cubic foot per second, so it takes 26,929.9 US gallons per hour to make one cubic foot per second.
What does this quantity actually measure?
Both units measure volumetric flow. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a US gallon per hour?
Used for fuel burn and small pumps.
What is a cubic foot per second?
The cusec — how American river gauges and water rights report flow.
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Is there a quick way to do GPH to cfs in my head?
Plenty of people do this in their head: divide by 27,000 instead of using the exact factor 0.000037. At 100 that shortcut gives 0.0037037037 cubic feet per second, off by 0.000010 cubic feet per second or about 0.26%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Us Gallons Per Hour to cubic feet per second reference tables
| Us Gallons Per Hour | Cubic Feet Per Second |
|---|---|
| 0.5 GPH | 1.85667e-05 cfs |
| 1 GPH | 3.71335e-05 cfs |
| 2 GPH | 7.4267e-05 cfs |
| 3 GPH | 0.0001114 cfs |
| 5 GPH | 0.000185667 cfs |
| 10 GPH | 0.000371335 cfs |
| 20 GPH | 0.00074267 cfs |
| 25 GPH | 0.000928337 cfs |
| 50 GPH | 0.00185667 cfs |
| 75 GPH | 0.00278501 cfs |
| 100 GPH | 0.00371335 cfs |
| 250 GPH | 0.00928337 cfs |
| 500 GPH | 0.0185667 cfs |
| 1000 GPH | 0.0371335 cfs |
| 5000 GPH | 0.185667 cfs |
Exact factor: 1 US gallon per hour = 3.71334876563e-05 cubic feet per second.
| Quantity | GPH | cfs |
|---|---|---|
| A dripping tap | 0.0951 GPH | 3.531e-06 cfs |
| A bathroom tap | 95.1 GPH | 0.003531 cfs |
| A shower head | 152.2 GPH | 0.00565 cfs |
| A garden hose | 285.3 GPH | 0.01059 cfs |
| A fire hydrant | 5.706e+04 GPH | 2.119 cfs |
| The Thames at London | 6.182e+07 GPH | 2295 cfs |
Published reference values, converted with the same factor this page uses.