Water Flow Rate Calculator

Calculate water flow rate in gallons per minute, gallons per hour, liters per minute, cubic feet per minute, and cubic feet per second. Use this calculator to estimate flow rate, total water volume, fill time, run time, fixture demand, and water cost.

Calculate Water Flow Rate

Water Flow Rate = Water Volume ÷ Time.
Your result will appear here.

How the water flow rate calculator works

Volume and time:
The calculator divides the water volume by the time to estimate flow rate.

Flow rate and time:
Enter a known flow rate and run time to estimate total water used.

Volume and flow rate:
Enter a volume and flow rate to estimate fill time or drain time.

Fixture demand:
Enter the number of fixtures, flow per fixture, and simultaneous use percentage to estimate total water demand.

Why use a water flow rate calculator?

A water flow rate calculator helps estimate how quickly water moves through a faucet, shower, hose, pipe, pump, tank, or irrigation outlet.

It can help compare GPM, GPH, liters per minute, cubic feet per minute, cubic feet per second, total water volume, run time, fill time, daily use, monthly use, and water cost.

What your result means

Your result shows estimated water flow rate, total water volume, fill time or run time, fixture demand, daily water use, monthly water use, and estimated water cost. These are planning estimates only. Real-world flow can vary based on water pressure, pipe size, hose size, filters, valves, fittings, elevation, fixture restrictions, and plumbing layout.

Water flow rate formulas

Frequently asked questions

How do you calculate water flow rate?

Divide the total water volume by the total time. For example, gallons divided by minutes gives gallons per minute.

What is the difference between water flow and water flow rate?

Water flow is the movement of water. Water flow rate measures how much water moves during a specific amount of time, such as gallons per minute.

How do you calculate fill time from flow rate?

Divide the total gallons needed by the gallons per minute flow rate. The result is the estimated number of minutes needed to fill the container.

Is this water flow rate calculator exact?

No. This calculator provides an estimate. Actual flow rate can change due to water pressure, pipe size, hose size, valves, filters, fittings, elevation, and fixture restrictions.