Quick answer
Flow rates convert through litres per second. 1 US gallon per minute equals 3.785412 litres per minute.
Enter a value and choose the flow units. The calculator returns the converted flow rate.
Related tools: Flow Rate Calculator: Volumetric flow rate from area and velocity, or volume and time. Data Transfer Rate Converter: Convert bps, Mbps, Gbps and bytes per second.
How to use the Flow Rate Converter
- Enter value.
- Choose from: Litre per second (L/s), Litre per minute (L/min), Litre per hour (L/h), Cubic metre per hour (m³/h), Cubic metre per second (m³/s) and US gallon per minute (GPM) and 4 more.
- Choose to: Litre per second (L/s), Litre per minute (L/min), Litre per hour (L/h), Cubic metre per hour (m³/h), Cubic metre per second (m³/s) and US gallon per minute (GPM) and 4 more.
- Enter decimal places (between 0 and 10). It starts at 4.
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Value | A number | — |
| From | Choose one: Litre per second (L/s); Litre per minute (L/min); Litre per hour (L/h); Cubic metre per hour (m³/h); Cubic metre per second (m³/s); US gallon per minute (GPM); US gallon per hour (GPH); Imperial gallon per hour; … | Starts at Litre per second (L/s) |
| To | Choose one: Litre per second (L/s); Litre per minute (L/min); Litre per hour (L/h); Cubic metre per hour (m³/h); Cubic metre per second (m³/s); US gallon per minute (GPM); US gallon per hour (GPH); Imperial gallon per hour; … | Starts at Litre per minute (L/min) |
| Decimal places | A number | ≥ 0, ≤ 10, starts at 4 |
Formula and method
Formula
result = value × (factor of source ÷ factor of target), base unit: litre per second
IEEE-754 double precision; displayed to the chosen number of decimal places (default 4). Very small or large results are shown in scientific notation.
Every unit is defined by an exact or published factor to the base unit (litre per second). The value is multiplied by the source factor and divided by the target factor.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Value = 1; From = US gallon per minute (GPM); To = Litre per minute (L/min); Decimal places = 6.
| Result | Value |
|---|---|
| US gallon per minute (GPM) → Litre per minute (L/min) | 3.785412 |
| Input | 1 US gallon per minute (GPM) |
Example 2
Inputs: Value = 1; From = Cubic foot per minute (CFM); To = Litre per minute (L/min); Decimal places = 6.
| Result | Value |
|---|---|
| Cubic foot per minute (CFM) → Litre per minute (L/min) | 28.316847 |
| Input | 1 Cubic foot per minute (CFM) |
Example 3
Inputs: Value = 1; From = Litre per second (L/s); To = Cubic metre per hour (m³/h); Decimal places = 2.
| Result | Value |
|---|---|
| Litre per second (L/s) → Cubic metre per hour (m³/h) | 3.6 |
| Input | 1 Litre per second (L/s) |
The first line is the headline result (uS gallon per minute (GPM) → Litre per minute (L/min)). Below it the flow Rate Converter lists input, which describe the same case from other angles. IEEE-754 double precision; displayed to the chosen number of decimal places (default 4). Very small or large results are shown in scientific notation.
Unit reference
Each unit expressed in the base unit used for the calculation. Conversions go through this base unit, so any unit can be converted to any other in the table.
| Unit | Equals (in litre per second) |
|---|---|
| Litre per second (L/s) | 1 |
| Litre per minute (L/min) | 0.01666666667 |
| Litre per hour (L/h) | 0.0002777777778 |
| Cubic metre per hour (m³/h) | 0.2777777778 |
| Cubic metre per second (m³/s) | 1000 |
| US gallon per minute (GPM) | 0.0630901964 |
| US gallon per hour (GPH) | 0.001051503273 |
| Imperial gallon per hour | 0.001262802778 |
| Cubic foot per minute (CFM) | 0.4719474432 |
| Cubic foot per second (cfs) | 28.31684659 |
Common conversions
1 L/min = 0.2642 gal/min, 1 m³/h = 16.67 L/min and 1 L/s = 3.6 m³/h. A garden hose delivers roughly 5 to 10 gallons per minute.
Fuel and fluids
Fuel pumps and injectors are rated in L/h or gal/h; cooling systems use L/min. Converting everything to one unit before comparing avoids errors of a factor of 60.
How the result changes with value
Holding every other input at the first worked example, this table changes only value. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Value | US gallon per minute (GPM) → Litre per minute (L/min) | Input |
|---|---|---|
| 0.5 | 1.892706 | 0.5 US gallon per minute (GPM) |
| 1 | 3.785412 | 1 US gallon per minute (GPM) |
| 2 | 7.570824 | 2 US gallon per minute (GPM) |
| 4 | 15.141647 | 4 US gallon per minute (GPM) |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Value: left empty shows "Enter value." beside that field and no result.
Choosing between the Flow Rate Converter and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Flow Rate Calculator](/science/flow-rate-calculator/) | use | Flow rate |
| [Data Transfer Rate Converter](/converters/data-transfer-rate-converter/) | value, from and to | Megabit per second (Mbps) → Megabyte per second (MB/s) |
| [Interest Rate Calculator](/finance/interest-rate-calculator/) | loan amount, monthly payment and term | Interest rate (APR) |
| [Cap Rate Calculator](/real-estate/cap-rate-calculator/) | net operating income and property value | Cap rate |
| [Churn Rate Calculator](/business/churn-rate-calculator/) | customers lost and customers at start | Churn rate |
Background: unit conversion
Many customary units are defined exactly in terms of metric ones: since the 1959 International Yard and Pound Agreement an inch is exactly 2.54 cm and a pound is exactly 0.45359237 kg (NIST SP 811 lists these). So most length and mass conversions are exact apart from the rounding of the displayed result.
To convert, multiply the value by the source unit's factor to reach the base unit, then divide by the target unit's factor; the unit table on this page lists every factor used. Temperature and fuel economy are the exceptions, because they are not simple multiples.
Assumptions and limitations
- Negative values are allowed
- Zero converts to zero (except L/100 km, where zero is invalid)
- Units from different quantities cannot be converted
- Very large or tiny results switch to exponent notation
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for value to confirm this.
Frequently asked questions
How many L/min is 5 gal/min?
About 18.9 litres per minute.
How many gallons per hour is 1 gpm?
60 gallons per hour.
Is imperial gallon supported?
Pick the imperial gallon unit if listed; it is 4.546 L.
What does the Flow Rate Converter calculate?
Convert litres, gallons and cubic metres or feet per second, minute and hour. It returns US gallon per minute (GPM) → Litre per minute (L/min) and Input.
What formula does the Flow Rate Converter use?
result = value × (factor of source ÷ factor of target), base unit: litre per second. Every unit is defined by an exact or published factor to the base unit (litre per second).
What is an example of a flow Rate result?
With value 1, from US gallon per minute (GPM), to Litre per minute (L/min) and decimal places 6, the uS gallon per minute (GPM) → Litre per minute (L/min) is 3.785412.
Where does the method come from?
The method follows: 1 US gallon = 3.785411784 L exactly; 1 imperial gallon = 4.54609 L exactly (NIST SP 811); 1 ft³ = 28.316846592 L exactly.
Related calculators
- Flow Rate Calculator — Volumetric flow rate from area and velocity, or volume and time.
- Data Transfer Rate Converter — Convert bps, Mbps, Gbps and bytes per second.
- Churn Rate Calculator — Share of customers lost over a period.
- Conversion Rate Calculator — Share of visitors who convert.
Sources
- 1 US gallon = 3.785411784 L exactly; 1 imperial gallon = 4.54609 L exactly (NIST SP 811)
- 1 ft³ = 28.316846592 L exactly
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.