AC Tonnage Calculator
Room size, floor, sun and people - the four things that decide your AC size. Get the answer in 10 seconds.
Your room
Which floor?
Sun exposure
Your AC size
0.8 Ton
Recommended tonnage
3,480 BTU
Estimated heat load
💡 A 0.8 ton AC covers this room comfortably. Do not oversize: a too-big AC short-cycles, dehumidifies poorly and costs more.
Rule of thumb: ~20 BTU per sq ft, plus top-floor and west-sun penalties, plus ~600 BTU per extra occupant. See our top 1.5 ton picks on the Appliances hub, ranked with running cost included.
Frequently asked questions
What size AC do I need for a 12x12 room?
A 144 sq ft room typically needs a 1 ton AC. Move to 1.5 ton if it is on the top floor, gets west sun, or regularly seats more than 3 people.
Is a bigger AC always safer?
No. An oversized AC short-cycles: it cools the air fast but removes humidity poorly and wastes power. Match tonnage to the room.
Does ceiling height matter?
These estimates assume the standard 9-10 ft ceiling. For double-height living rooms, add roughly 25% to the load and step up a size.