How to calculate GPM flow rate?

Divide the total gallons by the time in minutes. For other time units, convert first - divide by 60 for seconds or multiply by 60 for hours. For example: 10 gallons in 2 minutes = 5 GPM.

How many gpm at 60 psi?

GPM at 60 psi depends on pipe diameter and system design. A ½-inch pipe might flow 5-8 GPM, while a ¾-inch pipe could flow 10-15 GPM at 60 psi. The exact flow rate requires measuring actual volume over time.

Is 2.5 gallons per minute good for a well?

2.5 GPM is considered low for a residential well. Most homes need 6-12 GPM for adequate water supply. While 2.5 GPM might work for a small household with conservation measures, it may struggle during peak demand periods like multiple fixtures running simultaneously.

What would be the flow rate from a pipe in gallons per minute if a 55 gallon drum fills in 6 minutes and 15 seconds?

Convert 6 minutes 15 seconds to 6.25 minutes, then divide: 55 gallons ÷ 6.25 minutes = 8.8 GPM.

Gallons Per Minute (GPM) Calculator

Calculate how fast water flows through your system in gallons per minute.

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How Gallons Per Minute (GPM) Calculator Works

This calculator determines flow rate by dividing the total volume of water (in gallons) by the time it took to flow. The formula automatically adjusts for different time units - whether you measured in seconds, minutes, or hours.

Flow rate measurements are essential for sizing pumps, evaluating well performance, checking irrigation systems, and determining if your water supply meets household demands. Most residential applications need between 6-12 GPM for adequate performance.

You can measure flow rate by timing how long it takes to fill a container of known volume, then entering those values here. This method works for everything from garden hoses to well pumps to plumbing fixtures.

Gallons Per Minute (GPM) Calculator Formula Breakdown

Formula

Gallons per minute = Total gallons ÷ (Total time × Time conversion factor)

Variables Explained

Total GallonsThe volume of water that flowed during your measurement. You can measure this by timing how long it takes to fill a bucket, tank, or other container of known capacity. Use the container's stated capacity for accuracy.
Total TimeHow long the water took to flow the measured volume. This should be the actual time you observed, whether measured with a stopwatch, timer, or by noting start and end times.
Time UnitsThe unit of time you used for your measurement. The calculator converts between seconds, minutes, and hours automatically. Choose the unit that matches how you measured the time period.

Example Calculation

Given:

Total Gallons: 1,500 gallons
Total Time: 1.5
Time Units: Hours

Calculation:

1,500 gallons ÷ (1.5 hours × 60 minutes/hour) = 1,500 ÷ 90 = 16.67 GPM

Result:

16.67 GPM

Explanation

This example shows testing a well pump by measuring how long it takes to fill a 1,500-gallon tank. At 16.67 GPM, this would be considered excellent flow rate for most residential wells.

Tips for Using Gallons Per Minute (GPM) Calculator

💡For accurate measurements, use a container with known capacity rather than estimating volume. Even small errors in volume can significantly affect your GPM calculation.
💡When testing wells or pumps, let the system run for a few minutes before starting your measurement to ensure steady flow rates.
💡If measuring very fast flow rates, use a larger container and longer time period for more accurate results, as timing errors have less impact over longer durations.

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