GPM to CFS Converter
Convert US gallons per minute (GPM) to cubic feet per second (CFS). Divide by 448.831, or multiply by 0.00222801. CFS is the standard unit for river discharge, stormwater design and open channel hydraulics in the United States.
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GPM to CFS conversion resultFree download
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How It Works
GPM suits pumps and pipework, but once you move to channels, culverts, weirs and streamflow the numbers get large and US practice switches to cubic feet per second. One CFS is roughly 449 GPM, so a modest 900 GPM pump discharges about 2 CFS. Hydrologists, drainage engineers and permit applications almost always work in CFS.
GPM to CFS Formula
CFS = GPM × 0.00222801
One US gallons per minute equals 0.00222801 cubic feet per second. Going the other way, one cubic feet per second equals 448.831 US gallons per minute.
Worked Example
Converting 100 GPM:
100 × 0.00222801 = 0.222801 CFS
GPM to CFS Conversion Table
| GPM | CFS |
|---|---|
| 1 GPM | 0.00222801 CFS |
| 5 GPM | 0.01114 CFS |
| 10 GPM | 0.0222801 CFS |
| 25 GPM | 0.0557002 CFS |
| 50 GPM | 0.1114 CFS |
| 100 GPM | 0.222801 CFS |
| 250 GPM | 0.557002 CFS |
| 500 GPM | 1.114 CFS |
| 1000 GPM | 2.22801 CFS |
Going the other way? Use the CFS to GPM converter. For any other unit pair, the full flow rate converter handles all ten supported units.
FAQ
Common questions about converting US gallons per minute to cubic feet per second.
Frequently Asked Questions
How do I convert GPM to CFS?
Divide the GPM value by 448.831, or multiply by 0.00222801. For example, 1000 GPM / 448.831 = 2.228 CFS.
How many GPM is 1 CFS?
One cubic foot per second equals 448.831 US gallons per minute. This comes from 1 cubic foot being 7.48052 US gallons, multiplied by 60 seconds per minute.
Why is CFS used instead of GPM?
CFS keeps open channel and streamflow numbers manageable. A river carrying 500 CFS would be 224,000 GPM, which is unwieldy. US hydrology, stormwater regulations and water rights are conventionally expressed in CFS.
What is 100 GPM in CFS?
100 GPM equals 0.222801 CFS. For rough field work, dividing GPM by 450 is accurate to within about 0.3%.
Is CFS the same as cusecs?
Yes. "Cusec" is a contraction of cubic feet per second and means exactly the same thing. The term is more common in British, Indian and Australian irrigation practice, while US engineers usually write CFS.
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