BTU-code digits inside the model string. Paste your model number for an instant decode.
Always confirm against the data plate's rated capacity line — model ranges occasionally reuse digits for non-capacity codes, and the plate is authoritative.
| Capacity code | BTU/hr | Tons |
|---|---|---|
| 09 | 9,000 | 0.75 |
| 12 | 12,000 | 1.0 |
| 18 | 18,000 | 1.5 |
| 24 | 24,000 | 2.0 |
| 30 | 30,000 | 2.5 |
| 36 | 36,000 | 3.0 |
| 42 | 42,000 | 3.5 |
| 48 | 48,000 | 4.0 |
| 60 | 60,000 | 5.0 |
Amana American Standard Bryant Carrier Daikin Goodman Heil Hitachi Lennox LG Lloyd O General Panasonic Payne Rheem Ruud Samsung Trane Voltas Whirlpool York
On the data plate — a metal or foil sticker on the side or back of the outdoor unit (or behind the front panel on indoor split units). Use the model number, not the serial number, which encodes the manufacture date rather than capacity.
BTU-code digits inside the model string. Divide the BTU code by 12 to get tons.
Paste the model number from the outdoor unit's data plate into the decoder above — it applies Blue Star's nomenclature automatically. Example: IC318YNU = 1.5 tons.
Blue Star (India) embeds a two-digit shorthand capacity code that divides by 12 for tons; the standard steps are 09, 12, 18 and 24.
Modern strings such as IA318YLU or IC518DBTU begin with a compressor letter — I marks a smart-inverter system. A digit such as the 5 in IC518 is the star-rating; the trailing 18 is the capacity, so both decode to 1.5 tons.
Older and window units use shape prefixes such as WF (Window Fixed-speed) or HW (High Wall), e.g. WFA312LN → 12 → 1.0 ton. The decoder isolates the two-digit capacity cluster regardless of the surrounding characters.
The decoder above applies this nomenclature automatically. Capacity codes are nominal — always confirm against the rated-capacity line on the unit’s data plate.
Capacity decoding on this page follows Blue Star’s published model-number nomenclature. To confirm a unit’s actual rated capacity and efficiency, cross-check the authoritative references below.
Tonnage is derived from nominal cooling capacity: 1 ton = 12,000 BTU/hr ≈ 3.5 kW. Indian shorthand codes (e.g. 12, 18, 24) and metric kW classes both map to these nominal tonnages.
Model-number conventions and standards evolve, and manufacturers occasionally reuse digits for non-capacity codes — the rated-capacity line on the unit’s data plate is always authoritative. Figures here are for identification and planning, not a substitute for a professional load calculation.
Different brand? Back to the full 22-brand decoder. Sizing a replacement? Check what your space really needs with the AC tonnage calculator first — the old unit may have been mis-sized.