US GPM to L/s Converter
Convert US gallons per minute to litres per second for HVAC pump checks and chilled water flow calculations. Use the conversion factor and formula to compare flow rates accurately across US customary and metric units.
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GPM to L/s formula
L/s = US GPM × 0.063090196
US GPM = L/s ÷ 0.063090196
The factor is 0.063090196 L/s for each 1 US GPM. Going the other way, 1 L/s is 15.850323 US GPM.
GPM to L/s reference table
| US GPM | L/s |
|---|---|
| 5 | 0.315451 |
| 10 | 0.630902 |
| 25 | 1.57725 |
| 50 | 3.15451 |
| 100 | 6.30902 |
| 200 | 12.618 |
| 300 | 18.9271 |
| 500 | 31.5451 |
| 1,000 | 63.0902 |
| 2,000 | 126.18 |
Where this conversion is used
Chilled water, condenser water and hot water flow rates are given in US GPM on US pump curves, coil selections and chiller data, and in L/s on the metric schedules used across India and the Gulf. Use this conversion for pump schedules, coil and valve selection, and water balancing reports. This page uses the US gallon. The imperial (UK) gallon is larger, 4.54609 L against about 3.785 L, so check which gallon a data sheet means.
Worked example
A chiller data sheet shows a chilled water flow of 240 US GPM and the pump schedule is in L/s.
240 US GPM × 0.063090196 = 15.1416 L/s
Schedule the pump for about 15.14 L/s.
Common mistakes
- Using the imperial gallon. Older British data may be in imperial GPM, which is about 20 percent more flow for the same number.
- Confusing L/s with L/min or m³/h. One litre per second is 60 litres per minute.
- Mixing air and water units on the same sheet. L/s is used for both airflow and water flow, so label which one it is.
Related HVAC Tools & Resources
Frequently asked questions
How does GPM to L/s conversion work for HVAC flow checks?
Multiply US GPM by 0.0630902 to get L/s. This converts gallons per minute to litres per second, with 10 US GPM equal to approximately 0.631 L/s. A US GPM to L/s Converter applies the factor automatically.
How many US gallons per minute equal 1 L/s, and how do you reverse the calculation?
One litre per second equals approximately 15.8503 US GPM. For the reverse l/s to gpm conversion, multiply the L/s value by the lps to gpm conversion factor of approximately 15.8503 for US gallons.
How do US and Imperial gallons compare when converting HVAC flow rates?
No, a US gallon and an Imperial gallon are different sizes. One US gallon equals 3.785412 litres, while one Imperial gallon equals 4.54609 litres. This US GPM vs Imperial GPM distinction matters when comparing pump schedules and equipment specifications.
How can you convert L/s to L/min or m³/h for HVAC calculations?
Multiply L/s by 60 to get L/min, or by 3.6 to get m³/h. For example, 2 L/s equals 120 L/min or 7.2 m³/h. When checking a GPM to m³/h conversion chart, confirm that it uses US gallons.
Why do HVAC pump schedules use both US customary and metric flow units?
Pump schedules may follow different project specifications, manufacturer documents, or unit conventions. Convert values to the same unit and confirm the gallon type before comparing them. A US GPM to L/s Converter helps standardize flow values, while a chilled water flow rate converter supports flow comparisons for chilled water systems.
What should you check before using a flow value for pump selection?
Confirm the flow unit and gallon type, then check the required pump head and manufacturer performance data. An HVAC pump flow calculator may support flow checks, but it does not replace pump selection based on system requirements. Pressure and motor power require separate checks, such as a psi to kPa calculator or an HP to kW converter.
Can flow conversion confirm that a hydronic system is balanced?
No, unit conversion changes the way flow is expressed, not the actual flow distribution in the system. A hydronic balancing flow calculator may support calculations, but proper balancing also requires measured flow rates, design targets, and suitable adjustment procedures.
Does a flow converter replace duct sizing or other HVAC calculations?
No, a flow converter changes flow units only. A Free HVAC duct calculator serves duct-sizing needs, while pump selection and hydronic balancing require their own calculations and design inputs.