Enter the flow rate and choose the conversion direction into the calculator to determine the equivalent value in liters per second (L/s) or cubic feet per minute (CFM).

CFM to L/s Converter

Enter a flow rate and select the conversion direction to calculate the equivalent value.

CFM to L/s Formula

The following formulas are used to convert between cubic feet per minute and liters per second.

L/s = CFM × 0.471947
CFM = L/s × 2.11888

Variables:

  • L/s is the flow rate in liters per second
  • CFM is the flow rate in cubic feet per minute

To convert CFM to L/s, multiply the airflow in cubic feet per minute by 0.471947. To convert L/s to CFM, multiply the airflow in liters per second by 2.11888.

What is CFM to L/s Conversion?

CFM to L/s conversion is the process of changing a volumetric flow rate from cubic feet per minute, an imperial unit, into liters per second, a metric unit. These units are commonly used in HVAC, ventilation, airflow balancing, and equipment sizing. Because both units describe volume over time, the conversion is done using a constant multiplier.

Knowing how to convert between CFM and L/s makes it easier to compare manufacturer data, design specifications, and building code requirements that may use different unit systems.

How to Calculate CFM to L/s?

The following steps outline how to calculate the equivalent flow rate.


  1. First, determine the airflow value you want to convert.
  2. Next, identify whether the value is in CFM or in L/s.
  3. If converting from CFM to L/s, multiply the value by 0.471947.
  4. If converting from L/s to CFM, multiply the value by 2.11888.
  5. After calculating the result, verify your answer using the calculator above.

CFM to L/s Conversion Table

The table below lists several common airflow values in CFM and their equivalent values in L/s using the formula L/s = CFM × 0.471947.

Flow Rate (CFM)Flow Rate (L/s)
10 CFM4.72 L/s
25 CFM11.80 L/s
50 CFM23.60 L/s
75 CFM35.40 L/s
100 CFM47.19 L/s
150 CFM70.79 L/s
250 CFM117.99 L/s

Different standards, product catalogs, and software tools may use either CFM or L/s. Understanding the conversion factor helps you compare airflow ratings accurately and avoid unit errors in design or field work.

Example Problem:

Use the following variables as example problems to test your knowledge.

Example 1: Flow Rate = 250 CFM

Converted Flow Rate = 117.99 L/s

Example 2: Flow Rate = 20 L/s

Converted Flow Rate = 42.38 CFM