About this tool
The CFM per Ton Airflow Calculator is a free, in-browser HVAC tool that converts a cooling capacity into the required system airflow, or works backward from a known airflow to an equivalent tonnage. It uses the industry rule of thumb that a cooling system moves about 400 cubic feet per minute of air per ton of refrigeration: required CFM = tons × CFM-per-ton factor.
Everything runs locally in your browser with nothing uploaded. The per-ton factor is adjustable for the load type: the standard 400 CFM/ton suits most comfort cooling, while humid climates with a high latent (moisture) load use a lower 350 CFM/ton to keep coils cold enough to dehumidify, and dry climates with a high sensible load use 450 CFM/ton. You can enter the capacity as tons or as BTU/hr (tons = BTU/hr ÷ 12,000), and a reverse mode divides a measured CFM by the factor to estimate the tonnage it can serve.
Results show the required airflow, the tons and factor used, and the acceptable 350–450 CFM/ton band so you can check a measured airflow against the target range. Real systems should still be verified by measuring external static pressure and actual delivered airflow, but this rule-of-thumb check is the standard first pass installers use to confirm a blower is moving enough air.