AC Tonnage Calculator &
Room Size Guide (2026)
Stop guessing. Enter your room dimensions, floor level, and occupancy — get a precise tonnage recommendation in seconds, calibrated for Indian climate conditions.
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8+ years practical experience in AC / Plant Installation, Maintenance and Repair. HVAC Expert at S.R Enterprise under the authorized dealership of Hitachi. All data is verified against 2026 BEE Tariff Orders and manufacturer specifications.
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Input Mode
Fill in your room details and click Calculate to see your recommendation.
Pro Tip
Even a perfectly sized AC won't cool efficiently if filters are dirty. See our Maintenance Guide to keep performance at peak.
Quick Reference: What Tonnage Is Right for Your Room?
| Room Type | Size | Recommended | Monthly Cost |
|---|---|---|---|
| Study/Office | Up to 100 sq ft | 0.8 Ton | ₹700–900/mo |
| Small Bedroom | 100–120 sq ft | 1.0 Ton | ₹900–1,200/mo |
| Standard Bedroom | 120–150 sq ft | 1.5 Ton | ₹1,300–1,800/mo |
| Master Bedroom | 150–180 sq ft | 1.5 Ton | ₹1,300–1,800/mo |
| Small Hall | 180–220 sq ft | 2.0 Ton | ₹1,700–2,400/mo |
| Living Room | 220–300 sq ft | 2.0 Ton | ₹1,700–2,400/mo |
| Large Hall | 300–400 sq ft | 2.5 Ton | ₹2,100–3,000/mo |
Note: These are for standard rooms with 10 ft ceiling, good insulation, at 35°C ambient. Add 0.5T for top floor, south/west facing, or kitchen use.
AC Size Chart: Square Feet to Tons
A quick reference guide based on BEE 2026 standards and Indian climate conditions. Once you know your tonnage, check our Best 1.5 Ton ACs in India list.
* Add 10–15% to tonnage for top-floor rooms with direct roof exposure. Values based on standard 9–10 ft ceiling height.
AC Tonnage vs Room Size Guide India 2026
Match your room size to the correct AC tonnage. These recommendations are calibrated for Indian ceiling heights (9–10 ft) and standard insulation. For rooms with extreme sun exposure or top-floor placement, see the adjustment factors below.
* Based on standard 9–10 ft ceiling height and moderate insulation. Adjust upward for extreme sun exposure, top floors, or high occupancy. Always round up, never round down — undersizing wastes more electricity.
Adjustment Factors
Your room is unique. These adjustment factors help you fine-tune the base tonnage recommendation for your exact conditions. Add these to the base tonnage from the table above.
Top floor (direct sun)
Extra heat load from roof
South / West facing
Afternoon sun exposure
City above 42°C peak
Higher ambient temperature
Glass walls / large windows
Solar heat gain
Kitchen use
Cooking adds heat load
More than 4 people regularly
Human body heat
Example: A 150 sq ft room on the top floor with west-facing windows needs: 1.5T (base) + 0.5T (top floor) + 0.25T (west sun) = 2.25T — so go with a 2.5 Ton unit. When in doubt, always round up. Undersizing costs more in electricity than oversizing.
Why Tonnage Matters: The Cost of
Under-sizing vs. Over-sizing
Getting tonnage wrong is the #1 mistake Indian buyers make — and it costs thousands every year.
Under-sized AC
- ✕Runs continuously at 100% capacity — never reaches set temperature
- ✕Compressor overheats and wears out 2–3x faster
- ✕Electricity bill 20–35% higher than a correctly sized unit
- ✕Room never feels truly cool on peak summer days (45°C+)
- ✕Humidity stays high — feels muggy even when running
Over-sized AC
- ⚠Short-cycles: cools too fast, shuts off, restarts repeatedly
- ⚠Each start-up draws 3–5x normal current — spikes your bill
- ⚠Doesn't run long enough to dehumidify — room feels cold but clammy
- ⚠Higher upfront cost for capacity you'll never use
- ⚠Compressor short-cycling reduces lifespan significantly
The Right-Sized AC: What You Get
30–40%
Lower electricity bill vs. wrong-sized unit
2–3x
Longer compressor lifespan with correct sizing
100%
Dehumidification — truly comfortable air
Now that you know the right size, calculate the exact electricity bill for this AC on our homepage. And remember, even a 2-ton AC won't cool efficiently if not maintained.
Common Sizing Mistakes That Cost You Money
The most expensive mistake in AC buying isn't choosing the wrong brand — it's choosing the wrong size.
Why Undersized ACs Cost More
A 1-ton AC in a 180 sq ft room runs continuously at full load — consuming 25–30% more electricity than a correctly sized 1.5-ton unit. The compressor never gets to rest, overheats faster, and needs replacement 2–3 years sooner.
Why Oversized ACs Waste Money
A 2-ton AC in a 120 sq ft room short-cycles — cools too fast, shuts off, then restarts. Every startup draws 3–5x normal current. The room feels cold but clammy because the unit never runs long enough to dehumidify.
Buy right-sized from day one. A correctly sized AC saves you ₹4,000–7,000 every year.
Use our calculator above — or see best ACs by size
How to Measure Your Room for an AC
A 2-minute process that saves you from years of wrong cooling.
Step 1
Measure the Length
Stand at one wall and measure to the opposite wall in feet. Include any alcoves or bay windows in the measurement.
Step 2
Measure the Width
Measure the perpendicular wall. For irregular rooms, measure the longest dimension in each direction.
Step 3
Note Your Floor Level
Top-floor rooms absorb roof heat and need 10–15% more cooling capacity. Middle and lower floors have standard heat loads.
Step 4
Enter Into Calculator
Multiply Length × Width to get square footage, or use our slider. Add occupants and floor type for a precision result.
AC Tonnage & Room Size FAQ
Common questions about matching AC tonnage to your room size and conditions.
For a standard 200 sq ft room with normal insulation and ceiling height, 1.5T is usually sufficient. Add 0.25T if the room is on the top floor or has a west-facing wall. For a 200 sq ft living room with glass windows, consider a 2-ton unit.
Still unsure about your room size?
Use our interactive calculator above — enter your exact room dimensions, floor level, and sun exposure for a precise recommendation.
Open Calculator →Sizing Tips That Also Save Electricity
- Right tonnage = lower bills: An oversized AC short-cycles and wastes energy. An undersized AC runs non-stop. Right-sizing saves 15–25% annually.Save ₹300–600/month
- Choose 5-star inverter: For any tonnage you need, a 5-star inverter uses 57% less power than 1-star non-inverter. Most cost-effective choice.Save ₹700–1,400/month
- Top-floor? Add 0.5 ton: Roof heat absorption adds significant load. Top-floor rooms need 10–15% more capacity to maintain the same comfort.
Got your tonnage? Now find the perfect AC.
Match your tonnage to the right model — and know exactly what it'll cost to run.
Best 1-Ton ACs
Top picks for small rooms up to 120 sq ft — bedrooms, studies, and cabins.
Best 1.5-Ton ACs
India's most popular size — ideal for 120–180 sq ft rooms.
Best 2-Ton ACs
For large rooms, halls, and open-plan spaces above 180 sq ft.
Understand the tech? Now see how it saves you money.
Use our AC Savings Calculator to see your exact payback period and 5-year ROI.
Know Your Tonnage? See Exact Electricity Costs
Find out exactly how many watts your AC uses and what it costs per month — by tonnage and star rating.
Related Calculators & Buying Guides
Know Your Size? Now Calculate the Bill.
Use our AC Bill Calculator to see exactly how much your new AC will cost per month — and how much you save with a 5-star inverter model.
Go to AC Bill Calculator →