Calculator
CFS to GPM (cubic feet per second)
1 cfs = 448.8 gallons per minute = 1.98 acre-feet per day = 0.646 million gallons per day = 28.3 liters per second.
Conversions: 1 cubic foot = 7.48052 US gallons = 28.3168 liters, both fixed by the definitions of the foot and the gallon (231 cubic inches). So 1 cfs = 7.48052 × 60 = 448.831 gallons per minute; × 86,400 seconds ÷ 1,000,000 = 0.646317 million gallons per day; and 86,400 cubic feet a day ÷ 43,560 cubic feet per acre-foot = 1.9835 acre-feet per day. Flows are rates: the per-day figures assume the flow holds for 24 hours. Gauge flows are USGS daily means, provisional until USGS reviews them. Same constants as the water units converter.
Cite
Cubic feet per second: common flows
| Cubic feet per second | Gallons per minute | Acre-feet per day | Million gallons per day | Liters per second |
|---|---|---|---|---|
| 1 | 449 | 1.98 | 0.646 | 28.3 |
| 5 | 2,244 | 9.92 | 3.232 | 141.6 |
| 10 | 4,488 | 19.84 | 6.463 | 283.2 |
| 25 | 11,221 | 49.59 | 16.158 | 707.9 |
| 50 | 22,442 | 99.18 | 32.316 | 1,415.8 |
| 100 | 44,883 | 198 | 64.6 | 2,832 |
| 500 | 224,416 | 992 | 323.2 | 14,158 |
| 1,000 | 448,831 | 1,984 | 646.3 | 28,317 |
| 5,000 | 2,244,155 | 9,918 | 3,231.6 | 141,584 |
| 10,000 | 4,488,310 | 19,835 | 6,463.2 | 283,168 |
| 50,000 | 22,441,550 | 99,175 | 32,315.9 | 1,415,840 |
Western rivers in gallons per minute: latest daily flows
Each tracked river gauge's latest daily mean flow from USGS, converted with the same constants as the calculator. Dates differ by gauge because each reports on its own schedule.
| Gauge | Date | Flow (cfs) | Gallons per minute | Acre-feet per day | Million gallons per day |
|---|---|---|---|---|---|
| Columbia River at The Dalles | Oct 28, 2026 | 86,900 | 39,003,414 | 172,366 | 56,164.9 |
| Willamette River at Portland | Oct 28, 2026 | 8,800 | 3,949,713 | 17,455 | 5,687.6 |
| Sacramento River at Verona | Oct 28, 2026 | 7,180 | 3,222,607 | 14,242 | 4,640.6 |
| Colorado River at Lees Ferry | Oct 26, 2026 | 6,480 | 2,908,425 | 12,853 | 4,188.1 |
| Colorado River near Cisco | Oct 28, 2026 | 4,740 | 2,127,459 | 9,402 | 3,063.5 |
| Rio Grande at Otowi Bridge | Oct 28, 2026 | 4,270 | 1,916,508 | 8,470 | 2,759.8 |
| San Juan River at Farmington | Oct 28, 2026 | 2,870 | 1,288,145 | 5,693 | 1,854.9 |
| American River at Fair Oaks | Oct 28, 2026 | 1,200 | 538,597 | 2,380 | 775.6 |
| Salt River near Roosevelt | Oct 28, 2026 | 755 | 338,867 | 1,498 | 488.0 |
| Snake River above Jackson Lake | Oct 28, 2026 | 292 | 131,059 | 579 | 188.7 |
| Gunnison River below Gunnison Tunnel | Oct 28, 2026 | 273 | 122,531 | 541 | 176.4 |
| Yampa River near Maybell | Oct 28, 2026 | 232 | 104,129 | 460 | 149.9 |
| Boise River at Glenwood Bridge | Oct 28, 2026 | 229 | 102,782 | 454 | 148.0 |
How the conversion works
A cubic foot of water is 7.48 US gallons, and a minute has 60 seconds, so a flow of 1 cubic foot per second moves 448.8 gallons every minute. Over a full day, 86,400 seconds, the same flow moves 86,400 cubic feet: 1.98 acre-feet, or about 646,000 gallons. To go from gallons per minute back to cfs, divide by 448.8, so a 1,000 gpm well pump moves about 2.23 cfs. The Colorado River at Lees Ferry ran 6,480 cfs on Oct 26, 2026, about 2,908,425 gallons per minute or 12,853 acre-feet in a day.
Rivers, canals and dam releases in the United States are reported in cfs; well pumps and pipes in gallons per minute; city water systems in million gallons per day. A cfs is also not the same as a cfm: cubic feet per minute is the airflow unit for fans and ducts, 1/60 of a cubic foot per second. What does cfs mean? explains how gauges measure flow and why each river is read against its own median, and the streamflow tracker has every gauge's daily flow.
Common questions
How many gallons per minute is 1 cfs?
448.8 gallons per minute. A cubic foot holds 7.48052 gallons and a minute has 60 seconds: 7.48052 × 60 = 448.831.
How do you convert cfs to acre-feet per day?
Multiply cfs by 1.9835. One cfs for a day is 86,400 cubic feet, and an acre-foot is 43,560 cubic feet, so 100 cfs is about 198 acre-feet a day.
How many MGD is 1 cfs?
About 0.646 million gallons per day (646,317 gallons). Going the other way, 1 MGD is about 1.547 cfs.
How do you convert gpm to cfs?
Divide gallons per minute by 448.8. A 1,000 gpm pump moves about 2.23 cfs.
How many liters per second is 1 cfs?
28.3 liters per second. A cubic foot is 28.3168 liters. One cubic meter per second (a cumec) is about 35.3 cfs.