SettingsSettings for this calculationUS
The rated heating or cooling output in kilowatts.
Take this from the unit's nameplate or datasheet. Be careful to use the thermal output, not the electrical input — on a heat pump those differ by the coefficient of performance, often by a factor of three or more.
Equivalent output
11,940 BTU/hr
Converted using an exact defined factor of 3412.141633127968 BTU/hr per kW. Manufacturers round nameplate figures heavily, so a 3.5 kW unit is usually sold as 12,000 BTU/h rather than the exact 11,942.
- Conversion factor applied
- 3,412.14 BTU/hr per kW
They open the calculator with your figures already in it
kW to BTU/hr Calculator: 11,942 BTU/hr — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- 1 BTU/h is defined as 0.29307107017222 W (International Table), so 1 kW = 3412.1416 BTU/h
- Nominal cooling tonnage: 1 ton of refrigeration = 12,000 BTU/h
Inputs used
- Output (kW)
- 3.5
Intermediate steps
- Conversion factor applied
- 3,412.14 BTU/hr per kW
Confidence note: Converted using an exact defined factor of 3412.141633127968 BTU/hr per kW. Manufacturers round nameplate figures heavily, so a 3.5 kW unit is usually sold as 12,000 BTU/h rather than the exact 11,942.
What this calculation does not cover
- This converts a rating you already have. It is not a heat-loss or heat-gain calculation, so it cannot tell you whether that kilowatt figure is the right capacity for the space — sizing still needs a room-by-room load calculation against your own design conditions.
- The conversion does not know what your kilowatt figure represents. Thermal output, electrical input, and gas input on a net or gross calorific basis all appear as kW on datasheets and are all treated identically here. Compare output against output, or you flatter one machine over another before any arithmetic happens.
- Rating conditions do not travel with the number. A heat pump's kW figure is quoted at particular indoor and outdoor temperatures and falls away as it gets colder outside, and the same machine usually carries different heating and cooling ratings. The BTU/hr you get back describes only the single rating point you typed in.
- The answer is arithmetic, not a catalogue size. Equipment sells in nominal steps with a tolerance band around each, and nothing here snaps the figure to a size a manufacturer actually builds or tells you what the unit you order will test at.
- Nothing here sizes an electrical supply. BTU/hr is heat moved or produced, not power drawn — take circuit, breaker and cable sizing from the nameplate's running current and minimum circuit ampacity, never from a converted capacity.
Add the equipment this sizes
This result is a specification — 11,940 BTU/hr — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-02 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations2
- 1 BTU/h is defined as 0.29307107017222 W (International Table), so 1 kW = 3412.1416 BTU/h
- Nominal cooling tonnage: 1 ton of refrigeration = 12,000 BTU/h
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European and Australian equipment is rated in kilowatts while American catalogues, permits and rebate schedules still work in BTU per hour, so anyone specifying a US-market unit from a metric datasheet has to move between the two. The arithmetic is exact — a kilowatt is 3,412.14 BTU/h by definition — but the practical trap is rounding: the industry sells in nominal sizes, so a 3.5 kW output is marketed as a 12,000 BTU/h or one-ton unit even though the true conversion is 11,942 BTU/h. Specify against the nominal size the catalogue uses, and keep the exact figure for load calculations rather than for ordering. Note too that a heat pump's thermal output and its electrical draw are different numbers: converting the input power instead of the rated capacity will undersize the equipment by whatever its coefficient of performance happens to be.