How many gallons per minute is your water flow?
Flow rate = volume ÷ time. Time how long a container takes to fill, enter it below, and get GPM (and litres per minute) instantly.
Fill-time test
Flow rate
20.0 L/min
= 5.3 US GPM
A 10 L container filled in 30 seconds means your tap delivers about 20.0 L/min.
Flow = volume ÷ time. Time how long a known container takes to fill, fully open.
Common questions
- How do I calculate GPM?
- Flow rate = volume ÷ time. Fully open the tap, time how many seconds it takes to fill a container of known size, then divide the volume by the seconds and multiply by 60. A 5-gallon bucket filled in 30 seconds = 10 GPM.
- What is GPM?
- GPM means gallons per minute — how much water flows in one minute. It's the standard way to rate taps, shower heads, well pumps and supply lines. The metric equivalent is litres per minute (L/min).
- What is a good GPM for a house?
- Whole-house demand is usually 6–12 GPM depending on how many fixtures run at once. Individual fixtures are lower: a modern shower head is about 1.5–2.5 GPM and a kitchen faucet about 1.5 GPM.
- How do I measure my well or tap flow rate?
- Use the fill-time test: open the tap fully, time filling a bucket of known volume, and divide volume by seconds × 60. For a well, run it until the pressure tank cycles for a truer sustained rate.
New to flow rates? Read the full GPM guide →
Reference & education only. Not professional, engineering, or code-compliance advice. Estimates are based on published model codes; local amendments and your Authority Having Jurisdiction (AHJ) govern. Always verify against the current adopted code and a licensed professional before doing work.
Last reviewed 2026-06.