GPM to CFM Converter

Convert Gallons Per Minute to Cubic Feet Per Minute

Enter Value in Gallons Per Minute (GPM)

Result in Cubic Feet Per Minute (CFM)

Quick Conversions:

Conversion Formula

From US Gallons Per Minute to Cubic Feet Per Minute:

CFM = GPM × 0.133681

From Cubic Feet Per Minute to US Gallons Per Minute:

GPM = CFM × 7.48052

Since 1 US gallon equals approximately 0.133681 cubic feet, multiplying the flow rate in GPM by this conversion factor yields the equivalent flow rate in CFM.

Conversion Examples

Example 1: Converting 10 GPM to CFM

Start with the flow rate: 10 GPM
Apply the conversion formula: CFM = 10 × 0.133681
Calculate the result: CFM = 1.33681
Final answer: 10 GPM = 1.337 CFM

Example 2: Converting 50 GPM to CFM

Start with the flow rate: 50 GPM
Apply the conversion formula: CFM = 50 × 0.133681
Calculate the result: CFM = 6.68405
Final answer: 50 GPM = 6.684 CFM

Example 3: Converting 100 GPM to CFM

Start with the flow rate: 100 GPM
Apply the conversion formula: CFM = 100 × 0.133681
Calculate the result: CFM = 13.3681
Final answer: 100 GPM = 13.368 CFM

GPM to CFM Conversion Table

Gallons Per Minute (GPM)	Cubic Feet Per Minute (CFM)
1 GPM	0.1337 CFM
2 GPM	0.2674 CFM
3 GPM	0.4010 CFM
5 GPM	0.6684 CFM
10 GPM	1.3368 CFM
15 GPM	2.0052 CFM
20 GPM	2.6736 CFM
25 GPM	3.3420 CFM
30 GPM	4.0104 CFM
40 GPM	5.3472 CFM
50 GPM	6.6840 CFM
60 GPM	8.0208 CFM
75 GPM	10.0260 CFM
80 GPM	10.6944 CFM
90 GPM	12.0313 CFM
100 GPM	13.3681 CFM
150 GPM	20.0521 CFM
200 GPM	26.7361 CFM
250 GPM	33.4202 CFM
500 GPM	66.8403 CFM
1000 GPM	133.6806 CFM

Popular Flow Rate Conversions

GPM to Liters Per Minute

1 GPM = 3.785 L/min

Multiply GPM by 3.78541 to get liters per minute, commonly used in metric systems worldwide.

GPM to Cubic Meters Per Hour

1 GPM = 0.227 m³/h

Multiply GPM by 0.227125 for cubic meters per hour, frequently used in industrial applications.

CFM to Liters Per Second

1 CFM = 0.472 L/s

Convert CFM by multiplying by 0.471947 to get liters per second for precise flow measurements.

GPM to Cubic Inches Per Minute

1 GPM = 231 in³/min

Multiply GPM by 231 to convert to cubic inches per minute for smaller scale applications.

Other Flow Rate Conversions

From	To	Multiply By
GPM	CFM	0.133681
GPM	L/min	3.78541
GPM	L/s	0.0630902
GPM	m³/h	0.227125
GPM	m³/s	0.0000630902
CFM	GPM	7.48052
CFM	L/s	0.471947
CFM	m³/h	1.69901
CFM	m³/min	0.0283168
L/min	GPM	0.264172
L/s	GPM	15.8503
m³/h	GPM	4.40287

Applications of GPM and CFM

Water Systems and Plumbing

GPM measures liquid flow rates in water supply systems, plumbing fixtures, pumps, and irrigation systems. It helps determine pipe sizing, pump capacity, and water usage efficiency in residential, commercial, and agricultural settings.

HVAC and Ventilation

CFM quantifies air flow in heating, ventilation, and air conditioning systems. It determines the capacity of fans, blowers, air handlers, and ductwork, making it critical for climate control system design and performance evaluation.

Industrial Processes

Both measurements apply to industrial fluid handling, chemical processing, and manufacturing operations. Converting between GPM and CFM helps when dealing with systems that handle both liquids and gases at various temperatures and pressures.

Fire Protection Systems

GPM specifications define the flow capacity of fire sprinkler systems, fire hydrants, and fire pumps. These measurements are critical for meeting safety codes and providing adequate fire suppression capabilities.

Pool and Spa Equipment

Pool pumps, filters, and circulation systems use GPM ratings to specify their flow capacity. Proper flow rates maintain water quality, chemical distribution, and filtration efficiency.

Air Compressors and Pneumatic Systems

CFM ratings specify the air delivery capacity of compressors and pneumatic equipment. This measurement helps select appropriate equipment for manufacturing, construction, and automotive applications.

Frequently Asked Questions

How do you convert GPM to CFM?

To convert gallons per minute to cubic feet per minute, multiply the GPM value by 0.133681. This conversion factor comes from the relationship that 1 US gallon equals 0.133681 cubic feet. For example, 20 GPM equals 20 × 0.133681 = 2.674 CFM.

What is the difference between GPM and CFM?

GPM (gallons per minute) measures volumetric flow rate of liquids, while CFM (cubic feet per minute) typically measures volumetric flow rate of gases, particularly air. GPM is common in plumbing and water systems, whereas CFM is standard for HVAC, ventilation, and pneumatic systems.

Why would you need to convert GPM to CFM?

Converting GPM to CFM becomes necessary when comparing or integrating different systems that use different measurement standards, such as combining water flow data with air flow specifications in industrial processes, or when working with equipment specifications that use different units.

Is there a difference between US gallons and Imperial gallons in these conversions?

Yes, there is a significant difference. One US gallon equals 0.133681 cubic feet, while one Imperial gallon equals 0.160544 cubic feet. This means 1 Imperial GPM equals approximately 0.1605 CFM, compared to 0.1337 CFM for US gallons. Always verify which gallon type is being used.

What is a good CFM rating for different applications?

Required CFM varies by application. Bathroom exhaust fans typically need 50-80 CFM, kitchen range hoods require 100-400 CFM, whole-house ventilation systems may need 60-100 CFM per room, and air compressors for pneumatic applications can range from 2-20 CFM depending on the tools being powered.

How accurate do GPM to CFM conversions need to be?

Accuracy requirements depend on the application. For general planning and estimation, rounding to two decimal places suffices. For engineering specifications, regulatory compliance, or safety-critical systems like fire protection, use at least four decimal places and account for temperature, pressure, and fluid properties.

Can you use the same formula for all types of fluids?

The GPM to CFM conversion formula works for volumetric flow rates regardless of fluid type, as it converts between volume units. However, when dealing with gases, temperature and pressure significantly affect volume, so standard conditions must be specified for meaningful comparisons.

What other units can GPM be converted to?

GPM can be converted to numerous flow rate units including liters per minute (L/min), liters per second (L/s), cubic meters per hour (m³/h), cubic meters per second (m³/s), barrels per day, fluid ounces per second, and many others depending on regional preferences and industry standards.

Key Points About Flow Rate Measurements

Volume vs Mass Flow

GPM and CFM measure volumetric flow rate (volume per time), not mass flow rate. For mass flow calculations, you must also account for fluid density, which varies with temperature and pressure.

Standard Conditions

CFM measurements often reference standard conditions (typically 68°F and 14.7 psia). Temperature and pressure changes affect gas volume significantly, so always verify the reference conditions used.

System Pressure Drop

Actual flow rates in piping and duct systems depend on pressure drop, friction losses, elevation changes, and fitting resistances. Theoretical conversions provide ideal values that may differ from real-world performance.

Measurement Accuracy

Flow measurement accuracy depends on the instrumentation used. Flow meters, pitot tubes, orifice plates, and other devices have different accuracy ranges and suitability for various applications and fluid types.