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BTU to Tons

Find AC Tonnage by Model Number

Start with the rated cooling capacity. Use a model code only when its manufacturer documentation is verified.

Read the nameplate

Use the rated cooling capacity first. Model-number codes vary by manufacturer and product family.

Air conditioner

Example nameplate, not a real product. Layouts vary by manufacturer.

Select a label on the example nameplate to see what it means.

  1. Model number

    Codes vary by manufacturer

    Model-number codes vary by manufacturer and product family. Don't read tons from a model number unless the manufacturer's documentation for that exact family confirms the code.

  2. Cooling capacity

    This is the number to convert

    How much heat an AC removes each hour. AC labels often drop the '/hr'.

    Enter it below to see the size in tons.

  3. MCA and MOCP

    Electrical, not tonnage

    Cooling capacity does not determine breaker size. Check the equipment nameplate and installation instructions for minimum circuit ampacity (MCA) and maximum overcurrent protection (MOCP). Have a qualified installer apply the locally adopted electrical code.

  4. Refrigerant charge

    Refrigerant weight, not tons

    How much refrigerant the system holds, in pounds and ounces. It isn't refrigeration tons and doesn't tell you the cooling capacity.

Convert the rated capacity

Enter the cooling-capacity rating, not power input or refrigerant charge.

Cooling capacity

Converted rated capacity

2.9167 refrigeration tons

Sold as a 3 ton AC. Exact: 2.92 tons.

Open in the calculator

Supported model families

Some manufacturers put a capacity code in the model number, but where it sits and what it means vary by manufacturer and product family. A code is reliable only when the manufacturer's documentation for that exact family confirms it.

No model families are verified here yet, so this guide never reads tonnage from a model number. Use the rated cooling capacity on the nameplate instead.

Unknown model help

We can't verify a model from its number. Enter the rated BTU/hr value from the nameplate, or check the manufacturer's documentation for that exact model.

A system's rated capacity can depend on which indoor and outdoor units are used together, so check the documentation for your combination.

You don't need the serial number.