Quick Answer: Kilowatt-hours to BTU
One kilowatt-hour is approximately 3,412.14 BTU (1 kWh ≈ 3,412.14 BTU).
Conversely, 1 BTU ≈ 0.0002931 kWh.
Formula: BTU = kWh × 3,412.1416
Worked examples
- 1 kWh ≈ 3,412.14 BTU
- 2 kWh ≈ 6,824.28 BTU
- 3 kWh ≈ 10,236.42 BTU
Method and limitations
One kilowatt-hour equals 3,412.1416 British Thermal Units (IT definition). A BTU is the heat needed to raise one pound of water by one degree Fahrenheit. Calculations use full-precision constants; answers in this box are rounded for readability (≈ marks a rounded value) and the calculator shows up to 9 significant figures. BTU here is the International Table BTU (1,055.05585262 J). BTU is an amount of energy; equipment labels that say "BTU" usually mean BTU per hour, which is power.
Each factor is exact by definition, derived from exact definitions, or a documented conventional value — see the methodology and sources.
Conversion Formula
One kilowatt-hour equals 3,412.1416 British Thermal Units (IT definition). A BTU is the heat needed to raise one pound of water by one degree Fahrenheit.
Complete Guide to Kilowatt-hours to BTU Conversion
What is a kilowatt-hour?
A kilowatt-hour (kWh) is one kilowatt of power sustained for one hour — the unit on every electricity bill and the standard measure of battery and solar capacity.
What is a BTU?
A British Thermal Unit (BTU) is the energy required to raise one pound of water by one degree Fahrenheit. It remains the working unit of the North American heating, ventilation and air conditioning industry and of natural gas and heating oil markets.
How the Conversion Works
One Btu(IT) is 1,055.05585262 joules. A kilowatt-hour is 3,600,000 joules, so dividing gives 3,412.1416 BTU per kWh. HVAC ratings usually express power as BTU per hour, in which case dividing by 3,412.1416 gives kilowatts of thermal output.
Why This Conversion Matters
Heat pump and air conditioner catalogues quote capacity in BTU/h while electricity is metered in kWh. Without this conversion you cannot check whether a unit is correctly sized for a room, or estimate what it will cost to run.
Scientific Context
The BTU is defined relative to the specific heat capacity of water, which varies slightly with temperature. This is why several BTU definitions exist. The International Table BTU fixes the value at 1,055.05585262 J for engineering consistency.
Step-by-Step Conversion Guide
Follow these steps to convert kilowatt-hours to btu manually:
Start with your value in kilowatt-hours
Example: You want to convert 3 kWh
Apply the conversion formula
Use the formula: BTU = kWh × 3,412.1416
Calculate the result
3 kWh = 10,236.42 BTU
Verify your answer
Use our calculator above to double-check your manual calculation.
Quick Mental Math Tip
One kilowatt-hour equals 3,412.1416 British Thermal Units (IT definition). A BTU is the heat needed to raise one pound of water by one degree Fahrenheit.
Common Conversions
| Kilowatt-hours (kWh) | BTU (BTU) | BTU → Kilowatt-hours |
|---|---|---|
| 1 kWh | 3,412.14 | 1 BTU = 0.000293071 kWh |
| 2 kWh | 6,824.28 | 2 BTU = 0.000586142 kWh |
| 3 kWh | 10,236.4 | 3 BTU = 0.000879213 kWh |
| 5 kWh | 17,060.7 | 5 BTU = 0.00146536 kWh |
| 10 kWh | 34,121.4 | 10 BTU = 0.00293071 kWh |
| 12 kWh | 40,945.7 | 12 BTU = 0.00351685 kWh |
| 18 kWh | 61,418.5 | 18 BTU = 0.00527528 kWh |
| 24 kWh | 81,891.4 | 24 BTU = 0.00703371 kWh |
| 36 kWh | 122,837 | 36 BTU = 0.0105506 kWh |
| 50 kWh | 170,607 | 50 BTU = 0.0146536 kWh |
| 100 kWh | 341,214 | 100 BTU = 0.0293071 kWh |
When You'll Need This Conversion
Air conditioner sizing
Translate a BTU/h cooling rating into kilowatts to check it matches the room heat load.
Heat pump specification
Compare North American BTU ratings with European kW ratings when selecting equipment.
Energy audits
Normalise gas (BTU/therms) and electricity (kWh) into one unit for whole-building analysis.
Thermodynamics coursework
Convert between imperial and SI energy units in heat transfer problems.
Pro Tips for Accurate Conversions
Divide BTU/h by 3,412 for kW
This single step makes any American HVAC spec sheet readable to a European installer.
Watch for the missing "per hour"
Retail listings say "12,000 BTU air conditioner" but always mean 12,000 BTU/h.
Use COP or SEER for running cost
BTU output ÷ efficiency = electrical input. Never assume output equals consumption.
Common Mistakes to Avoid
Treating BTU output as electricity consumption
A heat pump moves several times more heat than the electricity it consumes.
Electrical input (kW) = thermal output (kW) ÷ COP.
Mixing BTU and BTU/h
One is energy, the other is power. Multiplying by hours twice is a common sizing error.
BTU/h × hours = BTU of energy delivered.
Using 3,400 as a shortcut for precise work
The 0.35% error is fine for a quick estimate but not for load calculations or billing.
Use 3,412.1416 for anything that will be specified or invoiced.
History & Background
The BTU dates to the 19th-century steam engineering tradition, where water and Fahrenheit were the natural references. It survived the metric transition because North American gas and HVAC infrastructure standardised on it.
Key Milestones
The BTU comes into use in British and American steam engineering.
The International Steam Table conference standardises the IT BTU value.
The IT BTU is fixed at 1,055.05585262 joules for engineering use.
US energy policy debates popularise the "quad" — one quadrillion BTU — as a national energy unit.
Global Usage Today
BTU dominates US, Canadian and Middle Eastern HVAC markets. Europe, Asia and Australia specify the same equipment in kilowatts, which is why cross-market conversion is constant.
Frequently Asked Questions
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Conversion factors on this page are either exact by definition, derived from exact definitions, or conventional values in documented use. Each is listed with its source in our conversion methodology and sources, which cites the BIPM SI Brochure, NIST Special Publication 811 and the relevant IEC or national standards. Results are rounded for display only; calculations use full precision.