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Air Change Rate Calculator

Adicot, Inc.'s Air Change Rate Calculator is a powerful tool for calculating the air changes per hour (ACH) in a room or building. Our calculator is easy to use and provides accurate results for a variety of applications. Whether you're an engineer, architect, or building owner, our calculator can help you determine the ventilation needs of your space.


  1. Select English or SI Units

  2. Select Input Criteria - the calculator will solve for the other value. 

    • Air Flow Rate​

    • Air Change Rate

  3. Enter the room height

  4. Select how to enter the room area: 

    1. Enter the area directly​

    2. Enter the length and width of the room

  5. Click the Calculate button

  6. The results will be displayed in the results window


Q =  ACH x V / C   

ACH = Q / V x C

where: Q = Aif flow rate, CFM [l/s]

ACH= Air change rate, 1/hr

           V = Room Volume ft^3 [m^3]

           C= 60 min/hr [3.6 m^3 x sec /l/hr]

Air Change Rate
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