AC Tonnage Calculator
Free AC tonnage calculator. Enter room size, sun exposure and kitchen to get the cooling capacity in BTU, tons and kW for the right air conditioner or mini-split size.
About the AC Tonnage Calculator
Estimate cooling capacity for a room from its dimensions, sun exposure, kitchen use and occupancy. The calculator uses an area-based lookup with adjustments, then rounds up to the next 1,000 BTU/hr. View BTU/hr, tons and thermal kW in imperial mode, or thermal kW in metric mode. This is a rough planning estimate, not an HVAC load calculation or confirmation that an installation meets local codes.
Features
- Cooling load in BTU/hr from room area
- Adjustments for sun exposure, kitchen and occupants
- Tonnage and thermal kW for sizing the unit
- Works for single rooms, additions and mini-splits
- 100% client-side and private — instant results, no signup
- Rounds estimates up to the next 1,000 BTU/hr
How to use this tool
The AC Tonnage Calculator works right in your browser — no signup, no installation. Follow these steps:
- Enter the room length and width in feet.
- Tick if the room is sunny or on the top floor, and if it includes a kitchen.
- Set the number of usual occupants.
- Read off the BTU, tons and kW you need.
Frequently asked questions
How is cooling capacity estimated?
The tool uses room-area capacity bands, adds 10% for sunny or top-floor rooms, 4,000 BTU/hr for a kitchen and 600 BTU/hr for each occupant beyond two. It rounds up to the next 1,000 BTU/hr.
Is this a professional HVAC load calculation?
No. Insulation, climate, window area, air leakage and other building details are not included. Use the result as a starting estimate.
What is a ton of cooling?
One ton equals 12,000 BTU/hr. Thermal kW describes cooling output, not electrical power use.
Using the results
The AC Tonnage Calculator estimates quantities from your measurements and the stated assumptions. Check dimensions, product coverage and project requirements before buying materials.