Liters Per Minute Calculator
Calculate water flow rate (LPM) from volume/time or cross-sectional area/velocity
Calculate Liters Per Minute
LPM = Volume ÷ Time
Measure collected liquid volume
LPM = Area × Velocity
Calculate from pipe dimensions
LPM = Volume ÷ Time
Volume = LPM × Time
Time = Volume ÷ LPM
Amount of liquid measured
Duration of water flow
Flow Rate Results
Formula: LPM = Volume ÷ Time
Inputs: Volume: 0.00 L, Time: 0.00 min
Quick Conversions
1 LPM = 0.264 GPM
1 LPM = 0.0353 CFM
1 LPM = 60 LPH
Example Calculation
6-inch Pipe Flow Rate
Pipe: 6-inch diameter circular pipe
Velocity: 20 inches per second
Method: Cross-sectional area × velocity
Calculation Steps
1. Cross-sectional area = π × (6 in / 2)² = 28.27 in²
2. Convert to metric: 28.27 in² = 182.4 cm²
3. Convert velocity: 20 in/s = 3,048 cm/min
4. Flow rate = 182.4 cm² × 3,048 cm/min = 556,000 cm³/min
Result = 556 LPM (approximately)
Common Flow Rates
Shower/Faucet
4-9 LPM
Water-saving fixtures
Garden Hose
20-60 LPM
Standard garden hose
Fire Hose
400+ LPM
Professional firefighting
LPM Measurement Tips
Use metric units for easier calculation
1 LPM ≈ 0.264 GPM conversion
Measure internal pipe diameter
Account for pressure variations
Consider pipe friction losses
Understanding Liters Per Minute (LPM)
What is LPM?
LPM (Liters Per Minute) is a metric unit that measures volumetric flow rate - how many liters of liquid flow through a system in one minute. It's widely used in plumbing, irrigation, and industrial applications worldwide.
Key Applications
- •Plumbing system design and specification
- •Irrigation and sprinkler system sizing
- •Pool and spa equipment selection
- •Industrial process flow measurement
- •Water treatment system design
Calculation Methods
Volume & Time Method
LPM = Volume (liters) ÷ Time (minutes)
Best for measuring actual flow rates with containers
Area & Velocity Method
LPM = Cross-sectional Area × Velocity
Calculate from pipe dimensions and flow velocity
Note: Ensure units are consistent: area in dm² and velocity in dm/min for direct LPM calculation (1 liter = 1 dm³).