HVAC Size and BTU Tool
AC Tonnage Calculator
Estimate air conditioner tonnage from square footage, ceiling height, insulation, sun exposure, climate, occupants, and heat load. Get BTU/h, AC tons, and the nearest common HVAC size.
BTU, Tons, and Common AC Sizes
Estimate AC Tonnage
Estimate cooling capacity from square footage, ceiling height, insulation, sun exposure, climate, occupants, and kitchen heat.
AC Tonnage Formula
AC tons = estimated BTU per hour / 12,000. The calculator starts from square footage, then adjusts for ceiling height, insulation, sun exposure, climate, occupants, and high-heat spaces.
Manual J vs Rule-of-Thumb Sizing
This page gives a planning estimate. Final HVAC sizing should use Manual J because ducts, windows, air leakage, orientation, humidity, and local design temperature can change the real load.
Why Bigger AC Is Not Always Better
Oversized equipment may cool quickly but cycle too often, remove less humidity, cost more upfront, and feel less comfortable. Undersized equipment may run constantly and still miss the thermostat setpoint.
Room, Apartment, and Whole-Home Use
Use room mode for a single-zone mini split or window unit. Use apartment or whole-home mode for broader estimates, then confirm with ductwork, load calculation, and equipment specifications.
AC Tonnage Chart by Square Feet
Frequently Asked Questions
How Do You Calculate AC Tonnage?+
Estimate cooling BTU per hour, then divide by 12,000. One ton of AC capacity equals 12,000 BTU/h.
How Many Square Feet Does 1 Ton of AC Cool?+
A rough estimate is often 400 to 600 sq ft per ton, but insulation, ceiling height, windows, sun exposure, and climate can change the result.
How Many BTU Is 1 Ton?+
One ton of air conditioning capacity equals 12,000 BTU per hour. A 2 ton system is about 24,000 BTU/h.
Is a 3 Ton AC Enough for 2,000 Sq Ft?+
It may be close in some homes, but final sizing depends on insulation, climate, windows, ceiling height, ductwork, and Manual J load calculation.