A flow rate converter translates between gallons per minute (GPM), liters per minute (LPM), cubic meters per hour, cubic feet per minute (CFM), and gallons per hour. Used for pump sizing, HVAC design, plumbing specifications, and irrigation planning.
Flow Rate Converter
Flow Rate Reference
| Application | GPM | LPM |
|---|---|---|
| Low-flow showerhead (WaterSense) | 1.5 | 5.7 |
| Standard showerhead | 2.5 | 9.5 |
| Kitchen faucet (standard) | 2.0 | 7.6 |
| Garden hose (5/8") | 13 | 49.2 |
| Fire hydrant (typical) | 500 | 1893 |
How to Convert Flow Rate Units
Flow rate unit conversion is common in plumbing, HVAC, irrigation, and industrial engineering. The US uses GPM (gallons per minute) for most residential plumbing; Europe and most of the world uses LPM (liters per minute) or m³/hr for larger systems.
Step 1: Key Conversions
1 GPM = 3.78541 LPM = 0.0630902 L/s = 0.227125 m³/hr. 1 CFM (cubic foot per minute) = 7.48052 GPM when converting liquid flow. For air flow, 1 CFM of air at standard conditions weighs about 0.0749 lb/min. The key thing to remember is that 1 US gallon = 3.785 liters, so multiply GPM by 3.785 to get LPM.
Step 2: Pump and HVAC Sizing
When sizing a pump, you need to know the required flow rate in GPM or LPM plus the total dynamic head (pressure loss). HVAC airflow is rated in CFM: a typical home requires 400 CFM per ton of cooling (1 ton = 12,000 BTU/hr). Converting between liquid and air flow requires knowing the fluid density since CFM is volumetric, not mass-based.
Step 3: Water Usage Calculations
Multiply flow rate by time to get total volume. A 10-minute shower at 2.5 GPM uses 25 US gallons (94.6 liters). A sprinkler at 2 GPM running for 30 minutes delivers 60 gallons (227 liters) to the lawn. Understanding flow rates helps calculate water bills and conservation opportunities.
FAQ
How do I convert GPM to LPM?
Multiply gallons per minute (GPM) by 3.78541 to get liters per minute (LPM). Example: 5 GPM × 3.78541 = 18.93 LPM. Going the other direction: multiply LPM by 0.264172 to get GPM. A standard kitchen faucet flows at about 2 GPM (7.6 LPM).
What is the difference between GPM and CFM?
GPM (gallons per minute) measures liquid flow, while CFM (cubic feet per minute) is typically used for air or gas flow in HVAC systems. They can be converted through the relationship 1 cubic foot = 7.48052 gallons, so 1 CFM = 7.48052 GPM if measuring liquid flow. For air flow, CFM is the standard unit in US HVAC specifications.
How much is a normal shower flow rate?
A standard showerhead flows at 2.5 GPM (9.46 LPM). Low-flow showerheads certified by EPA WaterSense use 2.0 GPM (7.57 LPM) or less. A 10-minute shower with a standard showerhead uses 25 gallons (94.6 liters). Replacing a 2.5 GPM head with 1.5 GPM saves 10 gallons per 10-minute shower.
What flow rate does a garden hose produce?
A standard 5/8" garden hose at normal house pressure (40-60 psi) flows at approximately 9-17 GPM (34-64 LPM). A 1" hose flows significantly more. Actual flow depends on hose diameter, length, and supply pressure.
Is this flow rate converter free?
Yes, completely free with no signup required. All conversions run instantly in your browser.