Flow Converter
ScienceConvert flow rate units including litres per minute, cubic metres per hour, GPM, and CFM. Ideal for plumbing, irrigation, and industrial engineering projects.
From
To
All conversionsfor 1 Litre per Minute (L/min)
| Cubic Metre per Second (m³/s) | 0.0000166667 |
| Cubic Metre per Minute (m³/min) | 0.001 |
| Cubic Metre per Hour (m³/h) | 0.060000072 |
| Litre per Second (L/s) | 0.0166667 |
| Litre per Minute (L/min) | 1 |
| Litre per Hour (L/h) | 60.000072 |
| Millilitre per Second (mL/s) | 16.6667 |
| Millilitre per Minute (mL/min) | 1000 |
| US Gallon per Minute (GPM) | 0.26417257 |
| US Gallon per Hour (GPH) | 15.850404 |
| Cubic Foot per Minute (CFM) | 0.035314771 |
| Cubic Foot per Second (CFS) | 0.00058857992 |
| UK Gallon per Minute (GPM) | 0.21996959 |
| UK Gallon per Hour (GPH) | 13.19821 |
What is a Flow?
A Flow Converter converts between units that measure volumetric flow rate — the volume of fluid (liquid or gas) passing a point per unit of time. Flow rate is expressed as volume ÷ time, so units like litres per minute (L/min), cubic metres per hour (m³/h), and gallons per minute (GPM) all measure the same physical quantity at different scales.
This converter covers 14 units across four systems: SI (m³/s, m³/min, m³/h), Metric (L/s, L/min, L/h, mL/s, mL/min), US Customary (GPM, GPH, CFM, CFS), and Imperial (UK GPM, UK GPH). This range covers domestic plumbing, irrigation design, HVAC, industrial process engineering, and laboratory flow measurement.
For Indian engineers and contractors, flow rate conversion is a daily requirement. Bureau of Indian Standards (BIS) specifications use metric units (L/min, L/s, m³/h), but a large share of pumps, compressors, and HVAC equipment is imported from the US with flow ratings in GPM or CFM. A pump rated at 10 GPM actually delivers 37.85 L/min — close enough to the Indian equivalent range, but the mental conversion is error-prone under time pressure.
Flow rate also connects to related concepts: use the Pressure Converter when working with pump head specifications, and the Volume Converter when dealing with tank capacities and fill-time calculations.
How to use this Flow calculator
- The converter loads with Litre per Minute (L/min) as the FROM unit and Cubic Metre per Hour (m³/h) as the TO unit — the most common pair in Indian engineering practice.
- Select your source unit from the FROM dropdown. Units are organised by group: SI, Metric, US Customary, and Imperial.
- Enter your flow rate value in the input field. The result updates immediately.
- Select your target unit from the TO dropdown.
- Use the ⇅ swap button to instantly reverse the FROM and TO units — useful when working backwards from a target flow rate.
- Scroll down to the reference table to see your value expressed in all 14 units simultaneously — helpful for writing specifications that must satisfy multiple standards.
- For pump selection, pair this result with the Pressure Converter to also convert the pump's head rating (bar ↔ psi ↔ metres of water column).
Formula & Methodology
This is a linear converter using the cubic metre per second (m³/s) as the common base unit. All conversions follow:Result = Input × (toBase_from ÷ toBase_to)Key toBase values (m³/s): | Unit | m³/s equivalent | |---|---| | Cubic Metre per Second (m³/s) | 1 | | Cubic Metre per Minute (m³/min) | 1.66667 × 10⁻² | | Cubic Metre per Hour (m³/h) | 2.77778 × 10⁻⁴ | | Litre per Second (L/s) | 1 × 10⁻³ | | Litre per Minute (L/min) | 1.66667 × 10⁻⁵ | | Litre per Hour (L/h) | 2.77778 × 10⁻⁷ | | Millilitre per Second (mL/s) | 1 × 10⁻⁶ | | Millilitre per Minute (mL/min) | 1.66667 × 10⁻⁸ | | US Gallon per Minute (GPM) | 6.30902 × 10⁻⁵ | | US Gallon per Hour (GPH) | 1.05150 × 10⁻⁶ | | Cubic Foot per Minute (CFM) | 4.71947 × 10⁻⁴ | | Cubic Foot per Second (CFS) | 2.83168 × 10⁻² | | UK Gallon per Minute (GPM) | 7.57682 × 10⁻⁵ | | UK Gallon per Hour (GPH) | 1.26280 × 10⁻⁶ | Worked example — pump selection in Bangalore: A residential building requires 90 L/min. A US-sourced pump is rated at 25 GPM. Is it sufficient?25 GPM × (6.30902 × 10⁻⁵) ÷ (1.66667 × 10⁻⁵) = 25 × 3.7854 = 94.6 L/minYes — 25 GPM exceeds the 90 L/min requirement by about 5%. Common reference conversions: | L/min | m³/h | GPM (US) | CFM | |---|---|---|---| | 10 | 0.6 | 2.64 | 0.353 | | 60 | 3.6 | 15.85 | 2.119 | | 100 | 6.0 | 26.42 | 3.531 | | 500 | 30.0 | 132.1 | 17.66 | Conversion factors are derived from the NIST definition of the US gallon (3.785411784 L exactly) and the Imperial gallon (4.54609 L exactly per UK Weights and Measures Act 1985). The cubic foot is based on the international foot definition of 0.3048 m exactly.
Frequently Asked Questions
What is a flow rate converter?
A flow rate converter converts between units that measure how much fluid — liquid or gas — moves past a point in a given time. Flow rate combines volume and time: for example, litres per minute (L/min) or cubic metres per hour (m³/h). This converter covers 14 units across SI, Metric, US Customary, and Imperial systems used in plumbing, irrigation, HVAC, and industrial engineering.
What is the difference between L/min and m³/h?
Both L/min and m³/h measure volumetric flow rate, just at different scales. One m³/h equals 16.667 L/min, since 1 m³ = 1000 L and 1 hour = 60 minutes. m³/h is commonly used for larger industrial systems like water treatment plants and HVAC ducts, while L/min is preferred for smaller systems like domestic water pumps, drip irrigation, and medical equipment.
How do I convert GPM to L/min?
To convert US gallons per minute (GPM) to litres per minute (L/min), multiply by 3.7854. For example, a 5 GPM pump delivers 5 × 3.7854 = 18.93 L/min. This conversion is frequently needed by Indian engineers and contractors working with US-manufactured pumps and HVAC equipment, where GPM is the standard rating unit but Indian specifications use L/min.
What flow rate units are used in India?
India primarily uses metric units for flow rate: litres per minute (L/min) and litres per second (L/s) for plumbing and irrigation, and cubic metres per hour (m³/h) for industrial and HVAC systems. The Bureau of Indian Standards (BIS) specifications and IS codes for water supply, sewerage, and HVAC all use these metric units. Cubic feet per minute (CFM) appears in some air-handling equipment ratings imported from the US.
What is CFM and when is it used?
CFM stands for cubic feet per minute, a unit of volumetric flow rate commonly used in HVAC, ventilation, and air compressor systems — especially in US and US-specification equipment. In India, CFM appears in air conditioning capacities, industrial vacuum ratings, and compressed air system specifications on imported equipment. One CFM equals approximately 1.699 m³/h or 28.317 L/min.
How many litres per minute is 1 m³/h?
One cubic metre per hour (m³/h) equals exactly 16.667 litres per minute (L/min). This is a fundamental conversion in pump selection and pipe sizing: if a pump is rated at 6 m³/h, it delivers 100 L/min. Divide m³/h by 0.06 to get L/min, or multiply L/min by 0.06 to get m³/h.
What is the difference between US GPM and UK GPM?
US GPM uses the US gallon (3.785 L), while UK GPM uses the Imperial gallon (4.546 L) — making UK GPM about 20% larger than US GPM. One US GPM = 3.785 L/min; one UK GPM = 4.546 L/min. When evaluating pump specifications from US manufacturers versus UK manufacturers, always confirm which gallon definition the rating uses to avoid under- or over-sizing the system.
How do I use the Flow Converter?
Select your source unit from the FROM dropdown — for example, Litre per Minute (L/min). Enter your flow rate value in the input field. Select the target unit from the TO dropdown — for example, Cubic Metre per Hour (m³/h). The converted result appears instantly. Use the ⇅ swap button to reverse the conversion, and scroll to the reference table to see your value in all 14 units at once.
What flow rate is typical for a household water pump in India?
A standard domestic water pump in India delivers between 20 and 60 litres per minute (L/min), depending on the motor size and head pressure. A 0.5 HP pump typically delivers around 25–30 L/min, while a 1 HP pump delivers 40–60 L/min at low head. In US specification terms, this corresponds to roughly 6 to 16 GPM. Always check the pump's performance curve, as flow rate drops as head pressure (height) increases.
How is flow rate related to pipe diameter and velocity?
Flow rate (Q), pipe cross-sectional area (A), and fluid velocity (v) are related by the formula Q = A × v. Doubling the pipe diameter quadruples the cross-sectional area, which either quadruples the flow rate at the same velocity or allows the same flow at one-quarter the velocity. This relationship is central to pipe sizing in plumbing and irrigation design, where velocity must be kept within acceptable limits to prevent noise, erosion, and pressure loss.
What flow rate does an irrigation drip system use?
Drip irrigation emitters typically deliver 2 to 8 litres per hour (L/h) per emitter. A field with 1000 emitters running at 4 L/h requires a supply flow of 4000 L/h = 66.7 L/min = 4 m³/h. Micro-sprinklers and sprinkler heads operate at higher rates — typically 30 to 150 L/h each. This converter is useful when comparing drip system specs, which are often quoted in L/h, against pump ratings in L/min or m³/h.
What is the formula for flow rate conversion?
All units in this converter are linear — they convert through a common base unit (cubic metres per second, m³/s) using: Result = Input × (toBase_from ÷ toBase_to). For example, to convert 100 L/min to m³/h: 100 × (1.66667 × 10⁻⁵) ÷ (2.77778 × 10⁻⁴) = 6 m³/h. This matches the intuitive calculation: 100 L/min × 60 min/h = 6000 L/h = 6 m³/h.