Gallons Per Minute Calculator
Calculate water flow rate (GPM), volume, or time with precise unit conversions
Calculate Water Flow Rate
GPM = Volume ÷ Time
Volume = GPM × Time
Time = Volume ÷ GPM
Amount of liquid measured
Duration of water flow
Flow Rate Results
Formula: GPM = Volume ÷ Time
Inputs: Volume: 0.00 US gal, Time: 0.00 min
Example Calculation
Garden Hose Flow Rate Test
Scenario: Measuring garden hose flow rate
Container: 5-gallon bucket
Fill time: 30 seconds
Method: Fill bucket and measure time
Calculation
GPM = Volume ÷ Time
GPM = 5 gallons ÷ 0.5 minutes
GPM = 10 gallons per minute
This represents a typical garden hose flow rate
Common Flow Rates
Shower/Faucet
1-2.5 GPM
Standard water-saving fixtures
Garden Hose
5-17 GPM
Varies by diameter and pressure
Fire Hose
100-500 GPM
Professional firefighting equipment
Flow Rate Tips
Measure actual flow with bucket and timer
Convert: 1 GPM ≈ 3.79 LPM
Larger pipe diameter = higher flow rate
Higher pressure = increased flow rate
Consider restrictions and pipe friction
Understanding Gallons Per Minute (GPM)
What is GPM?
GPM (Gallons Per Minute) is a unit of flow rate that measures how much liquid flows through a system in one minute. It's essential for sizing pumps, pipes, irrigation systems, and plumbing fixtures.
Applications
- •Plumbing system design and sizing
- •Irrigation and sprinkler system planning
- •Pool and spa equipment selection
- •Fire protection system design
- •Water well and pump sizing
Basic Formula
GPM = Volume (gallons) ÷ Time (minutes)
Measurement Tips
Bucket Test Method
- 1. Use a known-volume container
- 2. Time how long it takes to fill
- 3. Divide volume by time
- 4. Convert units as needed
Note: Actual flow rates depend on water pressure, pipe diameter, and system restrictions. Always verify with field measurements.