Calculate water flow rate, gallons per minute, cubic feet per second, pipe flow, velocity, water volume over time, and refill time. Use this water flow calculator for hoses, pipes, streams, irrigation lines, pond filling, lake inflow, drainage, pumps, waterfalls, and outdoor water planning.
Area × velocity:
The calculator multiplies a known flow area by water velocity to estimate flow rate.
Pipe diameter × velocity:
Enter pipe or hose diameter and velocity to estimate flow through a round pipe.
Volume ÷ time:
Enter a measured volume and the time it took to fill to calculate flow rate.
Fill time from flow rate:
Enter a known flow rate and target volume to estimate how long filling will take.
A water flow calculator helps estimate how fast water is moving and how much volume can be delivered over time.
It can be useful for ponds, lakes, hoses, pipes, irrigation lines, fountains, waterfalls, garden watering, pumps, streams, drainage, culverts, and outdoor water projects.
Your result shows estimated flow rate in gallons per minute, gallons per hour, cubic feet per second, liters per minute, cubic meters per second, acre-feet per day, total volume over time, fill time, and water cost estimate.
Multiply the flow area by water velocity. If area is in square feet and velocity is in feet per second, the result is cubic feet per second.
One cubic foot per second is about 448.83 gallons per minute.
Divide the target volume by the flow rate. For example, 5,000 gallons at 25 gallons per minute takes about 200 minutes.
Actual flow can be reduced by pipe friction, pressure loss, fittings, elevation changes, hose restrictions, pump limits, filters, valves, and debris.