Free tool
AC Tonnage Calculator
Find the right AC size for your room in seconds — no signup, no email required.
Length × width of the room, in feet.
How this is calculated
We use the commonly cited Indian sizing guideline of roughly 100 BTU of cooling per square foot (close to the standard "120 sq ft per ton" rule of thumb), add 10% for high sun exposure (top floor or west-facing rooms heat up faster), and add roughly 600 BTU for each occupant beyond two. The result is converted to tons (1 ton = 12,000 BTU) and rounded up to the nearest standard AC size — 1, 1.5 or 2 ton. This is a general guideline; a technician can give you an exact recommendation on-site, especially for irregular rooms or false ceilings.
Frequently asked questions
How many tons of AC do I need for a 120 sq ft room?
For a standard room with normal sun exposure and up to 2 occupants, a 120 sq ft room typically needs a 1 ton AC. Add 10% for a west-facing or top-floor room with high heat gain.
Is it bad to oversize an AC?
Yes. An oversized AC cools the room too fast without properly removing humidity, leading to a clammy feel, more on/off cycling, higher electricity bills, and faster wear on the compressor.
Does the number of people in the room matter?
Yes — each person adds body heat to the room. This calculator adds roughly 600 BTU of extra cooling capacity for every occupant beyond two.
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