Liters Per Minute Calculator
Convert liters per minute to any of six common flow units, or compute LPM from a real measurement. The converter at the top handles gallons per minute, cubic feet per minute, liters per second, liters per hour, cubic meters per hour, and cubic feet per hour. The bucket fill calculator below figures LPM from a volume you collected and the time it took.
Common LPM conversions
Type any LPM value into the converter and pick a target unit. The reference tables below show common LPM values converted to each target unit at a glance. Conversion factors come from NIST SP 811 and are exact to six significant figures.
Enter a flow rate in liters per minute.
Pick the unit you want LPM converted to.
| LPM | GPM |
|---|---|
| 1 | 0.3 |
| 5 | 1.3 |
| 10 | 2.6 |
| 25 | 6.6 |
| 50 | 13.2 |
| 75 | 19.8 |
| 100 | 26.4 |
| 200 | 52.8 |
1 LPM = 0.264172 GPM. Values rounded to one decimal.
| LPM | CFM |
|---|---|
| 1 | 0.04 |
| 5 | 0.18 |
| 10 | 0.35 |
| 25 | 0.88 |
| 50 | 1.77 |
| 75 | 2.65 |
| 100 | 3.53 |
| 200 | 7.06 |
1 LPM ≈ 0.0353 CFM. Two-decimal precision keeps small-LPM rows readable.
| LPM | L/s |
|---|---|
| 1 | 0.02 |
| 5 | 0.08 |
| 10 | 0.17 |
| 25 | 0.42 |
| 50 | 0.83 |
| 75 | 1.25 |
| 100 | 1.67 |
| 200 | 3.33 |
1 LPM = 1/60 L/s ≈ 0.0167 L/s. Two-decimal precision for small-LPM fidelity.
| LPM | L/h |
|---|---|
| 1 | 60 |
| 5 | 300 |
| 10 | 600 |
| 25 | 1,500 |
| 50 | 3,000 |
| 75 | 4,500 |
| 100 | 6,000 |
| 200 | 12,000 |
1 LPM = 60 L/h (definitional). Values are naturally large; whole-number precision is enough.
| LPM | m³/h |
|---|---|
| 1 | 0.1 |
| 5 | 0.3 |
| 10 | 0.6 |
| 25 | 1.5 |
| 50 | 3.0 |
| 75 | 4.5 |
| 100 | 6.0 |
| 200 | 12.0 |
1 LPM = 0.06 m³/h. One-decimal precision matches the /water default.
| LPM | CFH |
|---|---|
| 1 | 2.1 |
| 5 | 10.6 |
| 10 | 21.2 |
| 25 | 53.0 |
| 50 | 105.9 |
| 75 | 158.9 |
| 100 | 211.9 |
| 200 | 423.7 |
1 LPM ≈ 2.12 CFH. One-decimal precision matches the /water default.
Bucket fill calculator
Results
Bucket fill works best when you can hold the bucket steady and time the fill to the second. For pump or fixture flow specs, use the converter above instead. Conversion factors come from NIST SP 811 and are exact to six significant figures.
Need gallons per minute? Use the GPM Calculator →
How to use this calculator
- 01Enter your flow rate in liters per minute in the converter at the top of the page.
- 02Pick a target unit from the dropdown: gallons per minute, cubic feet per minute, liters per second, liters per hour, cubic meters per hour, or cubic feet per hour.
- 03Read the converted value next to the input. The reference tables below show common LPM values converted to each target unit.
- 04To compute LPM from a real measurement, use the bucket fill calculator. Enter the volume of water you collected and how long it took.
- 05Pick seconds or minutes for the time unit. Read the LPM result.
Understanding the math
Conversion multiplies your LPM value by the inverse of each NIST conversion factor. Each factor comes from NIST SP 811’s published unit definitions. The formulas below convert from LPM to each target unit directly.
GPM = LPM / 3.785412 CFM = LPM / 28.316847 L/s = LPM / 60 L/h = LPM × 60 m³/h = LPM / 16.666667 CFH = LPM / 0.471947
Worked example. A pump rated at 50 LPM converts to GPM. Source value is 50 liters per minute. The LPM-to-GPM divisor is 3.785412. 50 / 3.785412 = 13.21 GPM. Round to display precision and the converter shows 13.2 GPM.
Bucket fill mode treats LPM as a rate. Take the volume you collected, divide by the time it took, then scale to a one-minute window. The seconds-to-minutes scale factor is 60 because a minute holds 60 seconds. The math is the same whether your bucket holds 5 liters (1.3 gallons) or 50 liters (13.2 gallons); the rate scales linearly.
LPM = (volume_L / time_sec) × 60 LPM = volume_L / time_min
Worked example. A 19-liter bucket fills in 30 seconds. Volume is 19 liters. Time is 30 seconds. (19 / 30) × 60 = 38 LPM. The same fill in 0.5 minutes gives 19 / 0.5 = 38 LPM. Both forms produce the same answer because they describe the same fill.
Frequently asked questions
How to convert liters per minute to gallons per minute
Multiply LPM by 0.264172 to get GPM, or divide LPM by 3.785412. The two forms produce the same result because 1 / 3.785412 equals 0.264172. So 50 LPM equals 50 × 0.264172 = 13.21 GPM, or 50 / 3.785412 = 13.21 GPM either way. The converter at the top of this page handles the math automatically. Type in any LPM value and pick GPM as the target unit.
How to convert liters per minute to CFM
Divide LPM by 28.316847 to get CFM (cubic feet per minute). So 100 LPM equals 100 / 28.316847 = 3.53 CFM. CFM is most often used for compressed air and HVAC airflow rather than water flow, but the conversion factor is the same regardless of fluid because both units measure volumetric flow rate. The converter above handles this conversion when you pick CFM as the target unit.
How do you calculate liters per minute?
Two common ways. From a bucket fill, divide the volume you collected in liters by how long it took, then scale to a one-minute window. A 19-liter bucket filling in 30 seconds gives (19 / 30) × 60 = 38 LPM. From a known flow rate in another unit, multiply or divide by the conversion factor. 10 GPM converts to LPM by multiplying by 3.785412, so 10 × 3.785412 = 37.85 LPM. The bucket method works at any tap, hose, or fill point where you can collect water. The conversion method works when a pump, fixture, or pipe spec already lists flow in non-LPM units.
How much is 1 liter per minute?
1 LPM equals 0.264 gallons per minute, or about 0.017 liters per second. Over an hour, 1 LPM totals 60 liters (15.85 gallons). Over a day, 1 LPM totals 1,440 liters (380.4 gallons). For comparison, a low-flow shower head delivers around 7.6 LPM, while a fully open garden hose runs around 34 LPM at typical residential pressure.
How to convert liters per minute to liters per second
Divide LPM by 60 to get L/s (liters per second). The factor is exact: 60 seconds per minute. So 100 LPM equals 100 / 60 = 1.67 L/s. The reverse direction multiplies L/s by 60 to get LPM. Liters per second shows up in scientific and industrial flow specifications more often than in residential plumbing, where LPM is the everyday unit.
Can I use this calculator with imperial measurements?
Yes. The bucket fill calculator's input toggle accepts imperial units, so you can enter volume in gallons and time in seconds or minutes. The output stays in LPM regardless of input system, since this is the liters-per-minute calculator. If you'd prefer your output in gallons per minute, the GPM Calculator is linked in related calculators below.
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