1 cfs = 448.83 gallons per minute = 28.32 liters per second = 0.0283 cubic meters per second = 1.98 acre-feet per day.
Conversion table
| cfs | gal/min | L/s | m³/s | acre-ft/day |
|---|---|---|---|---|
| 1 | 449 | 28.32 | 0.0283 | 1.98 |
| 10 | 4,488 | 283 | 0.3 | 19.83 |
| 100 | 44,883 | 2,832 | 2.8 | 198 |
| 500 | 224,416 | 14,158 | 14.2 | 992 |
| 1,000 | 448,831 | 28,317 | 28.3 | 1,983 |
| 5,000 | 2,244,156 | 141,584 | 141.6 | 9,917 |
| 10,000 | 4,488,312 | 283,168 | 283.2 | 19,835 |
| 100,000 | 44,883,117 | 2,831,685 | 2,831.7 | 198,347 |
What cfs means
A flow of one cubic foot per second means a box of water one foot on each side passes a point every second. The U.S. Geological Survey measures river flow, called discharge, this way at thousands of stream gauges; the number on a gauge page is a cfs value calculated from the water level and a rating curve built from field measurements.
The factors are exact definitions, not estimates: a foot is 0.3048 meters, a U.S. gallon is 231 cubic inches, and an acre-foot is 43,560 cubic feet. That makes one cubic foot 7.48052 gallons, so 1 cfs is 448.83 gallons per minute and about 646,317 gallons per day.
For scale: a small creek in late summer may carry 5 to 20 cfs, a mid-size mountain river a few hundred to a few thousand, and the Mississippi at St. Louis typically well over 100,000 cfs.
Live examples from waterfall rivers
Latest USGS readings (provisional) at gauges near well-known falls, converted. More on the waterfall flow now page.
- Vernal and Nevada FallsUSGS 11264500: 9.05 cfs4,062 gal/min
- Snoqualmie FallsUSGS 12144500: 648 cfs290,843 gal/min
- Spokane FallsUSGS 12422500: 2,000 cfs897,662 gal/min
- Great Falls of the PotomacUSGS 01646500: 2,350 cfs1,054,753 gal/min
- Minnehaha FallsUSGS 05289800: 8.33 cfs3,739 gal/min
Questions
What does cfs mean?
Cfs stands for cubic feet per second, the standard unit USGS uses for river flow (discharge). One cubic foot is about 7.48 U.S. gallons, so 1 cfs is about 7.48 gallons every second.
How many gallons per minute is 1 cfs?
1 cfs = 448.83 gallons per minute (7.4805 gallons x 60 seconds).
How do I convert cfs to cubic meters per second?
Multiply by 0.0283168. For example, 1,000 cfs is 28.3 cubic meters per second.
What is an acre-foot per day?
The volume that would cover one acre one foot deep, delivered in a day. A steady 1 cfs adds up to 1.98 acre-feet per day.
Basis: exact unit definitions (NIST Handbook 44; U.S. survey of units). River examples: USGS Water Data API, provisional, public domain. Estimates for planning only.