LPM to L/s
1 Liter per Minute (LPM) = 0.0166667Liter per Second (L/s)
By KAMP Inc. / UnitOwl · Last reviewed:
How Many Liters per Second in a Liter per Minute?
One liter per minute (LPM) equals exactly 1/60 of a liter per second (L/s), or approximately 0.01667 L/s. To convert LPM to L/s, divide by 60. To convert L/s to LPM, multiply by 60. This is a simple within-metric time conversion — the volume unit (liters) stays the same, only the time base changes from minutes to seconds. The L/s unit is preferred in hydraulic engineering, fire protection (outside the US), and civil engineering drainage design, where flow rates are typically larger and the per-second basis aligns with other hydraulic calculations using meters and seconds. Australian and European plumbing codes specify fixture flow rates in L/s, while LPM is more common in medical and laboratory contexts. A household faucet at 8 LPM flows at 0.133 L/s. A storm drain handling 500 L/s processes 30,000 LPM. Because the conversion is exact, it is one of the quickest ways to make plumbing schedules, fire-flow calculations, and lab specs speak the same unit language across different standards. That exactness makes it a reliable checkpoint when moving between minute-based product literature and second-based hydraulic code tables.
How to Convert Liter per Minute to Liter per Second
- Start with your flow rate value in LPM.
- Divide by 60 to get L/s.
- For example, 120 LPM / 60 = 2.0 L/s.
- This is an exact conversion — no approximation involved.
- For the reverse, multiply L/s by 60 to get LPM.
Real-World Examples
Quick Reference
| Liter per Minute (LPM) | Liter per Second (L/s) |
|---|---|
| 1 | 0.0166667 |
| 2 | 0.0333333 |
| 5 | 0.0833333 |
| 10 | 0.166667 |
| 25 | 0.416667 |
| 50 | 0.833333 |
| 100 | 1.66667 |
| 500 | 8.33333 |
| 1,000 | 16.6667 |
History of Liter per Minute and Liter per Second
The choice between LPM and L/s reflects different engineering traditions. Medical and laboratory science adopted LPM because minute-based measurements aligned with clinical observation periods and human-scale processes (breaths per minute, heartbeats per minute). Civil and hydraulic engineering adopted L/s because seconds are the base SI time unit, and hydraulic formulas (Manning's equation, Bernoulli's equation) use seconds. Australian and European plumbing standards settled on L/s during metrication, while Asian standards often use LPM. The factor of 60 between them simply reflects the 60 seconds in a minute, making the conversion exact and trivial.
Common Mistakes to Avoid
- Multiplying by 60 instead of dividing when converting LPM to L/s. LPM values are always larger than L/s values (there are more liters in a minute than a second of flow). If your L/s result is larger than the LPM input, you went the wrong way.
- Confusing L/s with m³/s. 1 m³/s = 1,000 L/s. Large hydraulic systems use m³/s; smaller systems use L/s. A river flow of 50 m³/s = 50,000 L/s = 3,000,000 LPM.
- Not specifying whether flow rate is at actual conditions or standard conditions. For gas flows, temperature and pressure affect volume. Liquid flows are much less affected, but very hot liquids may differ.
- Assuming the unit conversion alone answers the design question. Converting 300 LPM to 5 L/s does not tell you whether the pipe, nozzle, or drain can actually carry that flow at the required pressure.
Frequently Asked Questions
When should I use LPM versus L/s?
How do L/s relate to m³/h?
What are typical flow rates in L/s for plumbing fixtures?
How many L/s is 30 LPM?
Is the LPM-to-L/s conversion exact?
The LPM-to-L/s conversion is just dividing by 60 — the same math you do when converting any rate from "per minute" to "per second." If a car travels 60 miles per minute, it travels 1 mile per second. The same logic applies: 60 LPM = 1 L/s. Use this as your mental anchor and scale from there.
Sources & References
- NIST — Units and Conversion Factors — Official unit conversion factors from the National Institute of Standards and Technology.
- BIPM — The International System of Units (SI) — International SI unit definitions from the International Bureau of Weights and Measures.