Flow rate (volumetric flow rate) measures the volume of fluid passing a point per unit time. The SI unit is cubic metres per second (m³/s). Practical units include litres per minute (L/min) for domestic pumps, CFM (cubic feet per minute) for HVAC, and GPM (gallons per minute) for US plumbing. Flow rate Q = velocity × cross-sectional area.

What is CFM and how do I convert it to L/min?

CFM stands for cubic feet per minute, the standard flow rate unit in US HVAC and industrial systems. 1 CFM = 28.317 L/min = 0.4719 L/s = 0.02832 m³/min. To convert CFM to L/min: multiply by 28.317. To convert L/min to CFM: divide by 28.317. A typical home HVAC system moves 400–1,200 CFM.

What is GPM in plumbing?

GPM (gallons per minute) is the US standard for plumbing and pump flow rates. 1 GPM = 3.785 L/min = 0.0631 L/s = 0.2271 m³/h. Typical values: shower head = 1.5–2.5 GPM, kitchen faucet = 1.5–2.2 GPM, garden hose = 9–17 GPM, fire hydrant = 500–1,000+ GPM.

How do I convert L/min to m³/s?

Divide by 60,000: 1 L/min = 1/60,000 m³/s ≈ 1.667 × 10⁻⁵ m³/s. This is because 1 L = 0.001 m³ and 1 min = 60 s, so 1 L/min = 0.001/60 m³/s. Example: 500 L/min = 500/60,000 = 0.00833 m³/s.

What flow rate is a typical water pump?

Common pump flow rates: Domestic booster pump = 20–50 L/min (5–13 GPM). Submersible well pump = 40–150 L/min (10–40 GPM). Irrigation pump = 100–500 L/min (26–132 GPM). Industrial centrifugal pump = 500–10,000 L/min (130–2,600 GPM). Fire pump = 1,900–7,600 L/min (500–2,000 GPM).

What is the difference between volumetric and mass flow rate?

Volumetric flow rate measures volume per time (m³/s, L/min, CFM). Mass flow rate measures mass per time (kg/s, lb/min). Mass flow = volumetric flow × fluid density. For water at 20°C (ρ = 998 kg/m³): 1 L/min volumetric ≈ 0.998 kg/min mass flow. Mass flow is preferred in chemical engineering where composition and density vary.

How do I convert m³/h to L/min?

Multiply by 1000/60 ≈ 16.667: 1 m³/h = 1,000 L / 60 min = 16.667 L/min. To convert L/min to m³/h: multiply by 0.06. Example: a pump rated at 300 L/min = 300 × 0.06 = 18 m³/h. This conversion is common in European HVAC and process engineering.

Flow Rate Converter

m³/s · m³/min · m³/h · L/s · L/min · ft³/s · CFM · GPM · gal/h

Convert flow rate units instantly — cubic metres per second, litres per minute, CFM, GPM and more. Click any row in the conversion table to set it as the target unit.

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1 m³/s = 1,000 L/s = 60,000 L/min | 1 CFM = 28.317 L/min | 1 GPM = 3.785 L/min

All Flow Rate Units — Click a row to select as target

Unit	Name	Value

About Flow Rate Units

Flow rate (volumetric flow rate) measures how much fluid passes through a cross-section per unit time. It is fundamental in hydraulics, HVAC, plumbing, chemical engineering, and environmental science. The SI unit is m³/s, but practical units vary widely by industry and region: L/min for European engineering, CFM for US HVAC, and GPM for US plumbing.

📏 SI & Metric Units

The SI unit m³/s is used in scientific and large-scale engineering. More practical metric units: m³/h is standard in European process engineering; L/s and L/min are used for pumps and pipe systems. Conversion chain: 1 m³/s = 1,000 L/s = 60,000 L/min = 3,600 m³/h.

🇺🇸 Imperial & US Units

CFM (cubic feet per minute) is the standard in US HVAC and compressed air systems. GPM (US gallons per minute) is standard for US plumbing, pumps, and irrigation. 1 CFM = 28.317 L/min = 0.4719 L/s. 1 GPM = 3.785 L/min = 0.0631 L/s. ft³/s (cusecs) is used in hydrology for river flow measurement.

Worked Examples

Shower Head

9 L/min = 2.38 GPM

= 0.15 L/s
= 0.318 CFM
= 0.54 m³/h
Low-flow shower head (standard is ~12 L/min)

Home HVAC System

600 CFM = 16,990 L/min

= 283 L/s
= 17.0 m³/min
= 1,019 m³/h
Typical 2,000 sq ft home air handler

Garden Hose

40 L/min = 10.6 GPM

= 0.667 L/s
= 1.414 CFM
= 2.4 m³/h
Standard ½-inch garden hose at full pressure

River (Small Stream)

1 m³/s = 1,000 L/s

= 60,000 L/min
= 35.31 ft³/s
= 2,119 CFM
Equivalent to ~264 GPM per second total

Who Uses Flow Rate Conversion?

♨️

HVAC Engineers

Convert between CFM (US equipment specs) and m³/h or L/s (European standards) when designing ventilation, air handling and cooling systems for buildings.

🚰

Plumbers & Plumbing Engineers

Calculate pipe sizing, pump selection and water supply capacity in GPM (US) or L/min (metric). Convert between systems when using international equipment datasheets.

🏭

Chemical & Process Engineers

Specify reactor feed rates, coolant flows, and product throughput in m³/h or L/min. Convert to mass flow (kg/h) using fluid density for material balance calculations.

🌊

Hydrologists

Measure river discharge in m³/s (cumecs) or ft³/s (cusecs). Convert between systems when comparing international river data and flood modelling standards.

🌿

Irrigation Engineers

Design drip and sprinkler systems in GPM (US) or L/h per emitter (metric). Convert pump flow ratings between systems for international equipment procurement.

🎓

Engineering Students

Convert flow rates for fluid mechanics assignments. Apply continuity equation Q¹ = Q² (A¹v¹ = A²v²) and Bernoulli problems requiring consistent SI units.

Mental Math Tips

CFM × 28.3 = L/min

1 CFM = 28.317 L/min. Quick: CFM × 28 gives a close approximation. Example: 100 CFM × 28 = 2,800 L/min (actual: 2,832). Reverse: L/min ÷ 28.3 = CFM. A 500 L/min pump × 28.3 = ~17.7 CFM.

GPM × 3.785 = L/min

1 US GPM = 3.785 L/min ≈ 3.8 L/min for quick estimates. Example: 50 GPM × 3.8 = 190 L/min (actual: 189.3). Reverse: L/min ÷ 3.785 = GPM. A 200 L/min pump = 200/3.785 ≈ 52.8 GPM.

m³/h × 16.67 = L/min

1 m³/h = 1,000 L ÷ 60 min = 16.67 L/min. Quick: m³/h × 17 for estimates. Reverse: L/min × 0.06 = m³/h. A pump at 300 L/min = 300 × 0.06 = 18 m³/h. Common in European HVAC datasheets.

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Frequently Asked Questions — Flow Rate Converter

Flow rate (volumetric flow rate) measures the volume of fluid passing a point per unit time. The SI unit is m³/s. Practical units: L/min for domestic pumps, CFM for HVAC, GPM for US plumbing. Flow rate Q = fluid velocity × pipe cross-sectional area.

CFM (cubic feet per minute) is the US standard for HVAC and compressed air. 1 CFM = 28.317 L/min = 0.4719 L/s. To convert CFM to L/min: multiply by 28.317. Reverse: L/min ÷ 28.317 = CFM. A typical home HVAC moves 400–1,200 CFM.

GPM (gallons per minute) is the US standard for plumbing and pump ratings. 1 GPM = 3.785 L/min = 0.0631 L/s. Typical values: shower head = 1.5–2.5 GPM, kitchen faucet = 1.5–2.2 GPM, garden hose = 9–17 GPM, fire hydrant = 500–1,000+ GPM.

Divide by 60,000: 1 L/min = 1.667 × 10⁻⁵ m³/s. Because 1 L = 0.001 m³ and 1 min = 60 s. Example: 500 L/min ÷ 60,000 = 0.00833 m³/s.

Domestic booster pump: 20–50 L/min (5–13 GPM). Submersible well pump: 40–150 L/min. Irrigation pump: 100–500 L/min. Industrial centrifugal pump: 500–10,000 L/min. Fire pump: 1,900–7,600 L/min (500–2,000 GPM).

Volumetric flow rate measures volume per time (m³/s, L/min). Mass flow rate measures mass per time (kg/s). Mass flow = volumetric flow × fluid density. For water at 20°C: 1 L/min ≈ 0.998 kg/min. Mass flow is used in chemical engineering where fluid density varies.

Multiply by 16.667: 1 m³/h = 1,000 L ÷ 60 min = 16.667 L/min. Reverse: L/min × 0.06 = m³/h. Example: 300 L/min × 0.06 = 18 m³/h. Common conversion in European HVAC and process engineering.

All Flow Rate Conversions

Common

m³/s → L/s L/s → m³/s m³/s → m³/h m³/h → m³/s L/s → L/min L/min → L/s m³/h → L/min L/min → m³/h

Metric

m³/s → m³/h m³/h → m³/s m³/s → L/s L/s → m³/s L/s → L/min L/min → L/s m³/s → L/min m³/h → L/s