Gallons per Minute to Cubic Feet per Second Converter

Accurate flow rate conversion between gal/min and ft³/s

Gallons per Minute gal/min

Cubic Feet per Second ft³/s

Quick Conversions:

Conversion Formula

Formula: ft³/s = gal/min × 0.002228010407594

Reverse Formula: gal/min = ft³/s × 448.831173401

The conversion factor between gallons per minute and cubic feet per second is based on the following relationships:

1 US gallon = 0.133680556 cubic feet
1 minute = 60 seconds

Therefore: 1 gal/min = (0.133680556 ft³) ÷ (60 s) ≈ 0.002228 ft³/s

Quick Reference Table

Gallons per Minute (gal/min)	Cubic Feet per Second (ft³/s)
1	0.002228010407594
5	0.01114005203797
10	0.02228010407594
25	0.05570026018985
50	0.1114005203797
75	0.1671007805696
100	0.2228010407594
150	0.3342015611391
200	0.4456020815187
250	0.5570026018984
500	1.114005203797
750	1.671007805696
1000	2.228010407594
1500	3.342015611391
2000	4.456020815187

Step-by-Step Conversion Examples

Example 1: Converting 20 gal/min to ft³/s

Step 1: Start with the value in gal/min = 20

Step 2: Apply the conversion factor: 20 × 0.002228010407594

Step 3: Calculate the result: 0.04456020815187 ft³/s

Example 2: Converting 150 gal/min to ft³/s

Step 1: Start with the value in gal/min = 150

Step 2: Apply the conversion factor: 150 × 0.002228010407594

Step 3: Calculate the result: 0.3342015611391 ft³/s

Example 3: Converting 500 gal/min to ft³/s

Step 1: Start with the value in gal/min = 500

Step 2: Apply the conversion factor: 500 × 0.002228010407594

Step 3: Calculate the result: 1.114005203797 ft³/s

Real-World Applications

Kitchen Faucet

A typical kitchen faucet flows at 2-3 gal/min, which equals approximately 0.0045-0.0067 ft³/s.

Garden Hose

Standard garden hoses deliver 5-10 gal/min, converting to about 0.011-0.022 ft³/s of water flow.

Fire Hydrant

Fire hydrants can deliver 500-1500 gal/min, equal to 1.11-3.34 ft³/s for firefighting operations.

Industrial Pump

Large industrial pumps may handle 1000-5000 gal/min, which translates to 2.23-11.14 ft³/s.

Water Treatment

Municipal water treatment plants process thousands of gal/min to supply cities with clean water.

HVAC Systems

Commercial HVAC systems use flow rates measured in both gal/min and ft³/s for cooling tower calculations.

Related Flow Rate Conversions

Frequently Asked Questions

What is the conversion factor from gal/min to ft³/s?

The conversion factor is 0.002228010407594. To convert gallons per minute to cubic feet per second, multiply the gal/min value by 0.002228010407594. This factor is derived from the relationship between gallons and cubic feet (1 gallon = 0.133680556 cubic feet) and the time conversion from minutes to seconds (divide by 60).

How do I convert ft³/s back to gal/min?

To convert cubic feet per second back to gallons per minute, multiply the ft³/s value by 448.831173401. For example, 1 ft³/s equals approximately 448.83 gal/min.

Why are both units used for flow rate measurements?

Gallons per minute is commonly used in plumbing, residential water systems, and smaller applications because it relates directly to everyday volume measurements. Cubic feet per second is preferred in engineering, hydrology, and river flow measurements as it aligns with standard engineering calculations and is part of the imperial system’s volumetric flow rate units.

What is the difference between US gallons and Imperial gallons?

A US gallon equals 3.785 liters (231 cubic inches), while an Imperial gallon equals 4.546 liters (277.42 cubic inches). This converter uses US gallons, which are standard in the United States. Imperial gallons are used in the UK and some Commonwealth countries. Always verify which gallon type is being referenced in your calculations.

Can this converter be used for gas flow rates?

While the mathematical conversion is the same regardless of the fluid type, these units are typically used for liquid flow rates, particularly water. Gas flow rates are more commonly measured in cubic feet per minute (CFM) or standard cubic feet per hour (SCFH) because gas volumes are more sensitive to pressure and temperature changes.

How accurate is this converter?

This converter uses the precise conversion factor of 0.002228010407594, providing accuracy to multiple decimal places. For most practical applications, rounding to 4-6 decimal places is sufficient. Always consider the precision requirements of your specific application.

What are typical flow rates in gal/min for household fixtures?

Typical household flow rates include: shower heads (2.0-2.5 gal/min), kitchen faucets (2.2 gal/min), bathroom faucets (1.5 gal/min), toilets (flush rate, not continuous), washing machines (15-30 gal/min during fill cycle), and dishwashers (1-3 gal/min). These rates help in sizing pipes and water heaters.

How does flow rate relate to pipe size?

Flow rate is determined by pipe cross-sectional area and fluid velocity. Larger pipes can accommodate higher flow rates at the same velocity, or maintain the same flow rate at lower velocities. The relationship is Q = A × V, where Q is flow rate, A is cross-sectional area, and V is average velocity. Proper pipe sizing prevents excessive pressure drop and maintains efficient flow.

About Flow Rate Units

Gallons per Minute (gal/min or GPM)

Gallons per minute is a volumetric flow rate unit that expresses the volume of liquid passing through a point in one minute. It’s widely used in the United States for measuring water flow in plumbing systems, pumps, wells, and irrigation systems. One US gallon equals 231 cubic inches or approximately 3.785 liters. This unit is practical for everyday applications because it directly relates to common volume measurements people encounter.

Cubic Feet per Second (ft³/s or CFS)

Cubic feet per second measures the volume flow rate where one cubic foot of material passes through a cross-section per second. This unit is commonly used in engineering applications, river flow measurements, and large-scale water management systems. The United States Geological Survey (USGS) uses CFS as the standard unit for reporting streamflow data. One cubic foot equals 1728 cubic inches or approximately 28.317 liters.

When to Use Each Unit

Choose gal/min for residential plumbing, small pumps, irrigation systems, water heaters, and appliance specifications. Opt for ft³/s when working with river flows, large water treatment facilities, drainage calculations, flood control systems, and civil engineering projects. Both units are part of the US customary system and can be easily converted using the factor provided in this converter.