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LPM to GPM

1 Liter per Minute (LPM) = 0.264172Gallon per Minute (US) (GPM)

By KAMP Inc. / UnitOwl · Last reviewed:

Result
0.264172 GPM
1 LPM = 0.264172 GPM
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How Many Gallons per Minute in a Liter per Minute?

One liter per minute (LPM) equals approximately 0.264172 US gallons per minute (GPM). To convert LPM to GPM, multiply the LPM value by 0.264172, or divide by 3.78541. This conversion is the reverse of GPM-to-LPM and is just as important. Engineers working with European or Asian pump specifications need to convert LPM ratings to GPM for American installations. Medical devices like oxygen concentrators are often rated in LPM (2-10 LPM for home use), and when cross-referencing with US medical equipment standards, GPM may be needed. Aquarium hobbyists encounter LPM on imported pump specifications and need GPM equivalents for US-market filter sizing guides. Industrial process engineers converting metric plant designs for US manufacturing facilities perform this conversion routinely. The conversion also matters in replacement work, because imported datasheets may list only LPM while US installers, codes, and pump tables still expect GPM. It is particularly helpful when small imported pumps or lab skids must be checked against US plumbing allowances, distributor catalogs, or tank-fill calculations. That keeps vendor comparisons and field substitutions honest.

How to Convert Liter per Minute to Gallon per Minute (US)

  1. Start with your flow rate value in LPM.
  2. Multiply the LPM value by 0.264172 to get GPM.
  3. For example, 50 LPM x 0.264172 = 13.21 GPM.
  4. Alternatively, divide LPM by 3.785 to get the same result.
  5. Quick estimate: divide LPM by 4 and add 5%. So 40 LPM / 4 = 10, plus 5% = 10.5 GPM (actual: 10.57).

Real-World Examples

An imported pump is rated at 100 LPM. What is that in GPM?
100 x 0.264172 = 26.42 GPM.
A medical oxygen concentrator delivers 5 LPM. Express in GPM.
5 x 0.264172 = 1.32 GPM. In medical contexts, LPM is the standard and GPM is rarely used.
A European car wash system uses 200 LPM of water. Convert to GPM.
200 x 0.264172 = 52.83 GPM.
An aquarium filter is rated at 30 LPM. What is the GPM equivalent?
30 x 0.264172 = 7.93 GPM. For a 55-gallon aquarium, this filter would circulate the tank about 8 times per hour.
A chemical dosing pump operates at 0.5 LPM. Convert to GPM.
0.5 x 0.264172 = 0.132 GPM. Very low flow rates like this are sometimes expressed in gallons per hour (7.93 GPH) for readability.

Quick Reference

Liter per Minute (LPM)Gallon per Minute (US) (GPM)
10.264172
20.528344
30.792516
51.32086
102.64172
153.96258
205.28344
256.6043
5013.2086
7519.8129
10026.4172
25066.043
500132.086
1,000264.172

History of Liter per Minute and Gallon per Minute (US)

The liter per minute became the standard international flow rate unit as SI adoption spread globally. The liter, originally defined in 1795 as the volume of one kilogram of water, pairs naturally with the minute to create an intuitive flow rate unit. In medical applications, LPM is universal — oxygen therapy, anesthesia gas delivery, and IV infusion rates worldwide use liters per minute (or milliliters per minute for very slow flows). The LPM standard in medicine dates to the adoption of the metric system in medical science during the 19th century. Today, LPM dominates in medical, scientific, and most international industrial contexts, while GPM remains the standard in American plumbing, HVAC, and fire protection.

Common Mistakes to Avoid

  • Multiplying by 3.785 instead of dividing by 3.785 (or instead of multiplying by 0.264). LPM values are always larger than GPM values for the same flow. If your GPM result is larger than the LPM input, the conversion went the wrong way.
  • Confusing LPM with L/s (liters per second). 1 L/s = 60 LPM. A pump rated at 2 L/s delivers 120 LPM (31.7 GPM), not 2 LPM.
  • Not specifying US or imperial gallons. 1 LPM = 0.2642 US GPM = 0.2200 UK GPM. The 20% difference between gallon definitions can cause significant sizing errors.
  • Rounding very small flows too early. A dosing pump or oxygen device at 0.5-5 LPM can lose meaningful accuracy if you round the GPM result too aggressively before finishing the calculation.
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Frequently Asked Questions

Is LPM used in the US at all?
Yes, in medical contexts. Oxygen flow rates, respiratory therapy, and anesthesia gas delivery in US hospitals all use LPM. A nasal cannula typically delivers 1-6 LPM of oxygen. This is the one area where even American practice uses LPM rather than GPM.
How do I size a pump when specifications are in LPM but my system uses GPM?
Convert the required flow rate to GPM (divide LPM by 3.785), then match to pump curves. Also convert head/pressure requirements: 1 meter of head = 3.281 feet. Always check that the pump curve's best efficiency point (BEP) matches your operating condition in the converted units.
What is the relationship between LPM and m³/h?
1 m³/h = 16.667 LPM (divide m³/h by 0.06, or multiply by 16.667). This is a simple metric-to-metric conversion since 1 m³ = 1,000 L and 1 hour = 60 minutes. Large industrial systems often use m³/h because the numbers are more manageable.
How many GPM is 60 LPM?
60 LPM equals about 15.85 GPM because 60 × 0.264172 = 15.85. That is a useful benchmark for medium residential pump and plumbing flows.
Why are oxygen concentrators rated in LPM instead of GPM?
Because patient oxygen flows are small, and liters per minute produces convenient numbers like 2, 4, or 6. Expressing those same values in GPM would create less intuitive decimals and would not match medical convention or clinician training.
Quick Tip

For a quick LPM-to-GPM conversion, divide by 4. This gives a result that is about 5% too low but is easy mental math. For greater accuracy, divide by 3.8. So 100 LPM is about 25 GPM (divide by 4) or 26.3 GPM (divide by 3.8). The exact answer is 26.4 GPM.

Sources & References