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Cubic feet per second to US GPM

CFS means cubic feet per second. To express that rate in US gallons per minute, convert the volume unit and the time unit separately.

Why the factor works

A cubic foot is 12 × 12 × 12 = 1,728 cubic inches. A US liquid gallon is 231 cubic inches. Thus one cubic foot is 576/77 US gallons. Multiply by 60 seconds/minute: one CFS is approximately 448.8311688 US GPM. Two CFS is approximately 897.6623377 US GPM.

Conversion table

Values below use unrounded factors and display up to ten significant digits.

Reverse the conversion

To convert US GPM back to CFS, divide by (576/77 × 60). Using 448.83 as a rounded factor may be adequate for an exercise that explicitly asks for it, but it does not reproduce every digit of the definition-based calculation.

Common unit mistakes

CFS is a rate, not a stored volume. Cubic feet alone cannot be converted to GPM without a time interval. These examples use US liquid gallons; an Imperial gallon has a different volume.

Use your own number

1. Open the matching calculator example.
2. Replace First value with your number.
3. Select Show worked calculation to see the updated result.
4. To reverse it, choose the starting unit and the desired answer unit.

Definitions and limits

US liquid gallon = 231 cubic inches = 3.785411784 liters. One cubic foot = 1,728 cubic inches. One cubic meter = 1,000 liters. Time conversions use fixed durations. See NIST’s conversion factors and our factors and rounding guide.

These are educational arithmetic examples. A rate is constant or an average over the stated interval. This tool does not supply operational decisions, dosing instructions or exam certification.

More worked conversions

• US gallons per minute to MGD
• Liters per second to cubic meters per hour

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