Best AC Tonnage Calculator — What Size AC Do You Need?
India's free tonnage calculator for AC sizing. Enter room dimensions, ceiling height, windows & occupancy — get instant tonnage (TR), BTU/h & kW for split, window or inverter AC.
Step 1 of 3
Location & building type
Location
Building type
How Our Best AC Tonnage Calculator Works
This free tonnage calculator helps you find the right AC size in India — room area, ceiling height, insulation, windows, local climate, occupants, lighting, and equipment heat. Built as the best AC tonnage calculator for bedrooms, halls, offices, and shops.
Location & building type
Select your Indian climate zone — North, Central, South, Coastal, or East — and building type: bedroom, living room, kitchen, office, shop/hall, or custom space. Each affects base envelope load and adjustments.
Room size & ceiling height
Enter length × width in feet or metres, or total area in sq.ft / sq.m. Ceiling height in feet or metres adjusts volume — important for Indian halls and independent houses with 10–12 ft ceilings.
Windows, sun & insulation
Window area in sq.ft or sq.m plus orientation (north, south, east, west) drives solar load — critical for top-floor flats and west-facing rooms in Indian summer.
People, lights & equipment
Each occupant adds ~120 W sensible heat. Enter lighting wattage and equipment load (computers, appliances). Results show tons (TR), kW, BTU/h, load breakdown, and recommended 0.75–3+ ton AC sizes.
AC Size Chart by Room Area — India (sq.ft & sq.m)
Quick reference for Indian homes with 8 ft ceilings and moderate insulation. Hot cities, top floors, large windows, or high ceilings need a larger tonnage — use the calculator above for split AC, window AC, or inverter AC sizing in TR and BTU.
| Area (sq.ft) | Area (sq.m) | Recommended AC size | Typical use |
|---|---|---|---|
| Up to 100 | Up to 9.3 | 0.75 ton | Small bedroom |
| 100 – 150 | 9.3 – 13.9 | 1 ton | Standard bedroom |
| 150 – 250 | 13.9 – 23.2 | 1.5 ton | Master bedroom, small living room |
| 250 – 350 | 23.2 – 32.5 | 2 ton | Large bedroom, medium living room |
| 350 – 500 | 32.5 – 46.5 | 2.5 ton | Large living room, small office |
| 500 – 700 | 46.5 – 65 | 3 ton | Medium office, restaurant dining area |
| 700 – 1000 | 65 – 93 | 4 – 5 ton | Large office floor, small shop |
| 1000 – 1500 | 93 – 139 | 5 – 7.5 ton | Large shop, small factory unit |
| 1500+ | 139+ | Consult engineer | Factory, warehouse, large hall |
These are general guidelines. Ceiling height above 8 ft, direct sunlight, or high occupancy will require a larger unit than shown.
AC Tonnage Calculator FAQ — Best Tonnage Calculator for India
Common questions about AC size, tonnage, BTU, and room coverage for Indian homes, offices, shops, and halls.
OneCalc.in is a free best-in-class AC tonnage calculator built for Indian homes and offices. Whether you searched for tonnage calculator, AC tonnage calculator, or AC tonn calculator — enter your room size, ceiling height, windows, and climate zone to get instant results in tons (TR), BTU/h, and kW with recommended split, window, or inverter AC sizes.
A 150 sq.ft bedroom in India typically needs a 1 ton split or window AC with an 8 ft ceiling, average insulation, and moderate sunlight. In hot cities like Delhi, Chennai, or Ahmedabad — or on a top floor with direct sun — upgrade to 1.5 ton for comfortable cooling without the unit running non-stop.
In Indian homes, 1 ton AC generally covers 100–150 sq.ft for bedrooms and 90–120 sq.ft for living rooms with standard 8–10 ft ceilings. Coastal and top-floor rooms with large windows may need 1.5 ton for the same area. Use our calculator with your exact dimensions, window area, and city climate for a precise result.
A 12×12 ft room is 144 sq.ft — usually a 1 ton AC is the right starting point for a bedroom. If the room has a 10 ft+ ceiling, west-facing windows, or you live in a very hot region, choose 1.5 ton. For a kitchen or hall with more heat load, 1.5 ton is often safer.
1 ton of AC equals 12,000 BTU per hour (12k BTU/h) of cooling capacity, or roughly 3.5 kW of cooling. A 1.5 ton AC delivers 18,000 BTU/h (~5.3 kW) and a 2 ton AC delivers 24,000 BTU/h (~7 kW). In India, ACs are sold in tonnage (TR) — our calculator shows tons, BTU/h, and kW together.
Our calculator adds envelope (wall) load, solar gain through windows, occupant heat (~120 W per person), lighting, equipment, and building-type adjustments. Results factor in ceiling height, insulation, sunlight, and Indian climate zones (North, Central, South, Coastal, East). Total cooling load is converted to tons (TR), BTU/h, and kW, then rounded to standard Indian AC sizes: 0.75, 1, 1.5, 2, 2.5, 3 ton and above.
Choose 1.5 ton for master bedrooms (150–250 sq.ft), small living rooms, or offices up to ~250 sq.ft with normal conditions. Choose 2 ton for living rooms (250–350 sq.ft), large bedrooms with high ceilings, or rooms with heavy sun exposure. Oversizing causes short-cycling and poor dehumidification — especially important in humid cities like Mumbai and Kolkata.
A 1000 sq.ft office in India typically needs 2 to 2.5 tons with standard 8–10 ft ceilings. Add capacity if you have many computers, servers, printers, or more than 10 occupants. Open-plan offices often benefit from multiple split units or a VRF system rather than one oversized unit.
Yes. Indian apartments often have 9–10 ft ceilings; independent houses and halls may have 12–16 ft. Higher ceilings mean more air volume to cool, so tonnage increases. Our calculator applies height factors automatically — enter height in feet or metres in Step 2.
Tonnage is the same whether you choose split or window AC — only the installation differs. Window ACs in India are common for 0.75–1.5 ton in bedrooms up to ~150 sq.ft. Split ACs are preferred for 1.5 ton and above, living rooms, and inverter models with 5-star BEE ratings for lower electricity bills.
Top-floor flats absorb more heat from the roof. Add 10–20% capacity versus a middle floor: a bedroom that needs 1 ton on a lower floor may need 1.5 ton on the top floor. Select your city location in Step 1, set high sunlight exposure, and enter roof-facing window area for an accurate estimate.
Halls and drawing rooms (200–400 sq.ft) in India usually need 1.5 to 2.5 ton depending on area, ceiling height, guest occupancy, and window size. Large marriage halls, shops, and showrooms need 3 ton or more — use the Shop/Hall building type and consult an HVAC engineer for spaces above 1,500 sq.ft.
Oversized ACs short-cycle — they cool quickly then shut off, leaving humidity high (a common complaint in monsoon and coastal India). Match the unit to your calculated load; pick the recommended size from our results. For high-humidity locations, the recommended tier already includes a small buffer.