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Calculation Machine

CFM per Ton Calculator

Airflow per ton of cooling capacity.

Reviewed by the Calculation Machine team · How we check our maths

Your values

ⓘ Live results

Results
CFM per ton
383
Target range
350–450 CFM/ton
Airflow at 400 CFM/ton
1,200 CFM
Difference from target
-50 CFM
Verdict
on target

Quick answer

Most cooling systems are designed for about 400 CFM per ton, lower in humid climates and higher in dry ones.

The formula

CFM per ton = airflow / tons

Worked example

Worked example

Using the values the calculator loads with.

Inputs

  • Measured airflow1150 CFM
  • System capacity3 tons

Result

  • CFM per ton383
  • Target range350–450 CFM/ton
  • Airflow at 400 CFM/ton1,200 CFM
  • Difference from target-50 CFM
  • Verdicton target

How to use the CFM per Ton Calculator

  1. 1Measure or read the delivered airflow in CFM.
  2. 2Enter the nominal capacity in tons (12,000 BTU/h per ton).
  3. 3Adjust blower speed if the ratio sits outside 350–450.

Frequently asked questions

Why 400 CFM per ton?

It balances sensible cooling and dehumidification for typical loads.

When should I run lower?

In humid climates 350–375 CFM per ton keeps the coil colder and pulls out more moisture.

About this calculator