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The rated output in BTU per hour, as printed on a US nameplate.
US residential air conditioning is commonly quoted in nominal tons — one ton is 12,000 BTU/h. Enter the BTU/h figure rather than the tonnage if you have it, since nominal tonnage is rounded.
Equivalent output
3.517 kW
Converted using an exact defined factor of 0.00029307107017222003 kW per BTU/hr. This is thermal output, not electrical consumption — do not size a circuit from it.
- Conversion factor applied
- 0 kW per BTU/hr
They open the calculator with your figures already in it
BTU/hr to kW Calculator: 3.52 kW — 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 = 0.29307107017222 W (International Table BTU), so 1000 BTU/h = 0.293071 kW
Inputs used
- Rated output (BTU/hr)
- 12000
Intermediate steps
- Conversion factor applied
- 0 kW per BTU/hr
Confidence note: Converted using an exact defined factor of 0.00029307107017222003 kW per BTU/hr. This is thermal output, not electrical consumption — do not size a circuit from it.
What this calculation does not cover
- The kilowatt figure is heat moved or produced, not electricity drawn. This is not an electrical load calculation and it gives you no minimum circuit ampacity, breaker size or conductor rating — take those from the unit's stated running current and its MCA and maximum overcurrent protection figures.
- US gas appliance nameplates commonly carry both an input firing rate and an output capacity, both stated in BTU/h. The conversion cannot tell which one you entered, so converting an input rating and treating the kilowatts as delivered heat overstates the output by whatever the appliance's efficiency is.
- The arithmetic is exact; the rating you feed it is not. Nominal tonnage and catalogue BTU/h figures are rounded sales sizes, and any capacity rating only holds at the conditions it was tested at — heat pump and air conditioner output both move with outdoor temperature. Nothing here derates the figure to your design condition.
- On cooling equipment the BTU/h rating covers total capacity, sensible plus latent. Converting it gives a total in kilowatts and says nothing about how much is available to drop air temperature rather than remove moisture, which is what governs performance in a humid space.
- This converts a number, it does not size anything. There is no heat loss or heat gain calculation behind it, no check that the capacity suits the building, and no check that the emitters, ductwork or pipework can actually deliver it.
Add the equipment this sizes
This result is a specification — 3.517 kW — 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 citations1
- 1 BTU/h = 0.29307107017222 W (International Table BTU), so 1000 BTU/h = 0.293071 kW
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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.
A contractor working to metric standards who has been handed American equipment specifications needs the reverse journey: a nameplate in BTU per hour, and a heat-loss calculation, supply sizing and paperwork that all expect kilowatts. The conversion is exact, but the number it produces is thermal output and not electrical demand, which is the mistake that matters here. Sizing a supply cable or a breaker from the converted figure will be badly wrong for anything other than direct resistive heating: a heat pump delivering 12,000 BTU/h of cooling draws nothing like 3.5 kW from the wall, and a gas appliance draws almost none at all. Use this figure for heat load and equipment matching, and take the electrical demand from the unit's stated running current instead.