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BTU to Watts Calculator

Convert between BTU/hr and watts for HVAC, heater, and appliance specs.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-25 · v1.0.0

Market
Imperial · sales tax

Converted power

1465.42 W

High confidence

For the dimensions entered, expect a converted power of 1465. Note that power sits at the low end of the range this calculator was checked against, so treat the output as indicative rather than settled. Set for United States against IRC 2024. The market selector changes both the units and the code cited.

Add the equipment this sizes

This result is a specification — 1,465.416 W — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • 1 watt = 3.412 BTU/hr

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

Why do some appliances use watts and others use BTU/hr?
Electric appliances (space heaters, electric baseboard) are typically rated in watts since that's the electrical input measure, while HVAC equipment (air conditioners, furnaces) is traditionally rated in BTU/hr, a measure of heating or cooling output — you'll often need to convert to compare them directly.
Is this the same as an air conditioner's 'ton' rating?
Related but different — 1 ton of air conditioning capacity equals 12,000 BTU/hr, so convert tons to BTU/hr first (multiply by 12,000), then use this calculator to get watts if needed.
Does this account for equipment efficiency?
No — this is a pure unit conversion between BTU/hr and watts of the same energy quantity, not an efficiency conversion between a gas appliance's fuel input and its heat output, which involves an efficiency rating (like AFUE).