British thermal unit.
BTU to Watt-hours Converter — BTU to Wh
Convert BTU (BTU) to Watt-hour (Wh) using the exact conversion factor (1 btu = 0.2930710702 watt-hour). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
BTU to Watt-hours converter
Converter
Energy Converter
Convert joules, calories, kilowatt-hours, BTU, electronvolts, therms, and mechanical work units.
Context values
Some unit families need one extra value for a physically accurate result.
A watt-hour is 3,600 joules.
Result = input x 1055.055853 / 3600.
Energy uses the joule as the base unit.
Reserved above the conversion cards and below the converter.
About Converting BTU to Watt-hours
BTU and Watt-hour both measure energy, and the conversion is especially useful for comparing nutrition labels (kilocalories) against scientific energy figures (joules). BTU is typically associated with united States (HVAC, heating, and appliance energy ratings), while Watt-hour is typically associated with universal — standard consumer-electronics and battery energy unit worldwide.
Formula
watt-hours = btu × 0.293071070172
This factor comes from each unit's defined relationship to the category's base unit: 1 btu equals 1055.05585262 base units, and 1 watt-hour equals 3600 base units, so dividing one by the other gives the direct btu-to-watt-hour factor of 0.293071070172.
Simple example
1 BTU × 0.2930710702 = 0.2930710702 Wh
1 btu = 0.2930710702 watt-hours.
Real-world example
100 BTU × 0.2930710702 = 29.30710702 Wh
100 btu = 29.30710702 watt-hours.
Conversion table
| BTU (BTU) | Watt-hour (Wh) |
|---|---|
| 1 BTU | 0.2930710702 Wh |
| 10 BTU | 2.930710702 Wh |
| 100 BTU | 29.30710702 Wh |
| 500 BTU | 146.5355351 Wh |
| 1,000 BTU | 293.0710702 Wh |
| 2,000 BTU | 586.1421403 Wh |
Reverse conversion: Watt-hour to BTU
0.2930710702 Wh × 3.412141633 = 1 BTU
0.2930710702 watt-hours = 1 btu.
btu = watt-hours × 3.41214163313
For a page dedicated to this direction, see Watt-hour to BTU.
BTU vs. Watt-hour
| Aspect | BTU | Watt-hour |
|---|---|---|
| Family | US customary unit | metric derived energy unit |
| Typical use | Air conditioner and furnace capacity ratings in the US | Phone, laptop, and power-bank battery capacity ratings |
| Where it's used | United States (HVAC, heating, and appliance energy ratings) | Universal — standard consumer-electronics and battery energy unit worldwide |
Understanding the BTU
BTU (BTU) measures energy. A British thermal unit is defined as exactly 1,055.05585262 joules (the International Table BTU). It is classified as a US customary unit.
Where it's used: United States (HVAC, heating, and appliance energy ratings)
Uses of the BTU today
- Air conditioner and furnace capacity ratings in the US
- Water heater and appliance energy specifications
- US energy industry (natural gas is often billed via BTU content)
History of the BTU
The BTU originated in 19th-century steam engineering as the heat needed to raise one pound of water by one degree Fahrenheit, paralleling the calorie's metric definition. Several slightly different BTU values existed historically before the 'International Table' BTU was standardized at exactly 1,055.05585262 joules.
Historical origin. BTU was not the invention of a single named person; it developed through the process described above.
Understanding the Watt-hour
Watt-hour (Wh) measures energy. The energy delivered by one watt of power sustained for one hour — equal to 3,600 joules. It is classified as a metric derived energy unit.
Where it's used: Universal — standard consumer-electronics and battery energy unit worldwide
Wh vs. kWh. The same unit at different scales: 1,000 Wh equals 1 kWh. Wh suits small consumer-electronics batteries; kWh is used for household electricity billing and larger energy storage.
Uses of the Watt-hour today
- Phone, laptop, and power-bank battery capacity ratings
- Electric-vehicle battery capacity specifications
- Small-scale renewable energy (solar panel) output ratings
BTU — sources
- NIST Special Publication 811 — Documents the International Table BTU's exact joule equivalence.
Watt-hour — sources
- BIPM SI Brochure — Watt-hour as a common energy unit derived from the coherent SI units watt and second (via the hour).
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many watt-hours are in 1 btu?
1 btu equals 0.2930710702 watt-hours, using the exact defined conversion factor rather than an estimate.
How do I convert btu to watt-hour?
Multiply the btu value by 0.2930710702. The converter above does this instantly to whatever precision you set.
How do I convert watt-hour back to btu?
Use the reverse factor: 1 watt-hour equals 3.412141633 btu. You can also use the swap control in the converter above to flip the direction instantly.
What is a btu?
BTU (BTU) measures energy. A British thermal unit is defined as exactly 1,055.05585262 joules (the International Table BTU). It is classified as a US customary unit.
What is a watt-hour?
Watt-hour (Wh) measures energy. The energy delivered by one watt of power sustained for one hour — equal to 3,600 joules. It is classified as a metric derived energy unit.
Is the btu to watt-hour conversion exact?
Yes. A British thermal unit is defined as exactly 1,055.05585262 joules (the International Table BTU). That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between wh vs. kwh?
The same unit at different scales: 1,000 Wh equals 1 kWh. Wh suits small consumer-electronics batteries; kWh is used for household electricity billing and larger energy storage.
Where is the btu still used today?
United States (HVAC, heating, and appliance energy ratings)