Gallon (US) per Hour to Cubic Foot per Minute (gal/h to CFM)
Convert gal/h to CFM — Flow Rate converter
One gallon (US) per hour equals 0.0022280093 CFM, so to convert gallons (US) per hour to cubic feet per minute you multiply the value by 0.0022280093. A gallon (US) per hour is smaller than a cubic foot per minute — going the other way, 1 CFM = 448.831169 gal/h. For example, 10 gal/h = 0.02228009 CFM and 50 gal/h = 0.11140046 CFM.
1 gal/h = 0.0022280093 CFM
Gallon (US) per Hour to Cubic Foot per Minute formula
1 Gallon (US) per Hour = 0.0022280093 CFM
Worked examples
- 25 gal/h = 0.05570023 CFM
- 100 gal/h = 0.22280093 CFM
Gallon (US) per Hour to Cubic Foot per Minute conversion table
| Gallon (US) per Hour (gal/h) | Cubic Foot per Minute (CFM) |
|---|---|
| 1 | 0.0022280093 |
| 2 | 0.0044560185 |
| 3 | 0.0066840278 |
| 5 | 0.01114005 |
| 8 | 0.01782407 |
| 10 | 0.02228009 |
| 12 | 0.02673611 |
| 15 | 0.03342014 |
| 20 | 0.04456019 |
| 25 | 0.05570023 |
| 50 | 0.11140046 |
| 100 | 0.22280093 |
| 250 | 0.55700231 |
| 500 | 1.114005 |
| 1000 | 2.228009 |
Which gallon, and which trade
The single most expensive mistake in flow conversion is the gallon. A US liquid gallon is 3.785411784 litres; an imperial gallon is 4.54609 litres. US GPM and imperial GPM differ by about 20%, and pump datasheets frequently do not say which one they mean. Check the manufacturer's country of origin before trusting a GPM figure.
Different trades default to different units for the same physical quantity: HVAC and compressed air work in CFM, plumbing and pumps in GPM or LPM, and process and water engineering in m³/h or L/s. A specification that mixes them is usually quoting different equipment, not different flows. On this page, 1 gal/h = 0.0022280093 CFM.
CFM to metric is worth memorising: one cubic foot is exactly 0.028316846592 m³, so 1 CFM = 1.699011 m³/h and 1,000 CFM ≈ 1,699 m³/h. Note that CFM on a compressor may be quoted as free air delivery (FAD) at inlet conditions rather than at working pressure — the two are not interchangeable.
Frequently asked questions
How many cubic feet per minute are in one gallon (US) per hour?
One gallon (US) per hour equals 0.0022280093 cubic feet per minute (CFM).
How many gallons (US) per hour are in one cubic foot per minute?
One cubic foot per minute equals 448.831169 gallons (US) per hour (gal/h).
How do you convert gallons (US) per hour to cubic feet per minute?
1 Gallon (US) per Hour = 0.0022280093 CFM. Use the calculator above for any value.
What is 5 gal/h in CFM?
5 gal/h = 0.01114005 CFM.
What is 100 gal/h in CFM?
100 gal/h = 0.22280093 CFM.
What is 10 gal/h in CFM?
10 gal/h = 0.02228009 CFM.
What is 20 gal/h in CFM?
20 gal/h = 0.04456019 CFM.
What is 50 gal/h in CFM?
50 gal/h = 0.11140046 CFM.
What is 500 gal/h in CFM?
500 gal/h = 1.114005 CFM.
Is a gallon (US) per hour bigger than a cubic foot per minute?
No. A gallon (US) per hour is smaller — one gallon (US) per hour equals 0.0022280093 cubic feet per minute, while one cubic foot per minute equals 448.831169 gallons (US) per hour.