BTU to kWh Converter
Instantly convert BTU to kilowatt-hours, watt-hours, joules, therms, kilocalories, and more — with live precision control, quick presets for common HVAC & appliance ratings, composite kWh & Wh display, and a downloadable PDF report.
Uses the IT (International Table) BTU: 1 BTU = 1,055.05585 J, so 1 kWh = 3,412.142 BTU and 1 BTU = 0.00029307 kWh — for reference only.
| BTU | Kilowatt-hours | Watt-hours | Kilojoules |
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BTU to kWh Conversion — Complete Guide for 2026
Converting BTU (British thermal units) to kWh (kilowatt-hours) is how you put heating, cooling, and gas figures on the same scale as your electric bill. Air conditioners, furnaces, water heaters, and gas bills are rated in BTU or therms, while electricity, solar panels, batteries, and EV chargers are measured in kilowatt-hours. The key relationship is: 1 kWh = 3,412.14 BTU, so 1 BTU ≈ 0.000293071 kWh (0.2931 Wh).
Our free BTU to kWh Converter takes a value in BTU and returns kilowatt-hours at 0 to 8 decimal places, splits the result into whole kWh plus leftover watt-hours (10,000 BTU becomes 2 kWh 931 Wh), and converts across the energy ladder — watt-hours, joules, kilojoules, megajoules, US therms, and kilocalories. Quick presets, a log-scale comparison chart, a common-values reference table, and a downloadable PDF report make it useful for a quick check or for energy audits and utility comparisons.
How to Use the BTU to kWh Converter in 4 Steps
A complete BTU-to-kWh conversion takes a few seconds. Enter an energy value or tap a preset, choose your precision, and download a PDF report you can attach to an energy audit, HVAC quote, or utility comparison.
Enter Your Energy in BTU
Type any value in BTU — from a single appliance run to millions of BTU of annual heating. For an HVAC rating in BTU per hour, enter the BTU delivered over the time you care about (for example, 12,000 BTU/h × 1 hour = 12,000 BTU).
Or Tap a Quick Preset
Common values are one tap away: 3,412 BTU (1 kWh), 5,000, 10,000, 12,000 (1 ton), 24,000 (2 ton), and 100,000 BTU (1 therm). The active preset stays highlighted, and typing a matching value re-selects it automatically.
Set Decimal Precision
Use the input or slider to pick 0 to 8 decimal places for the kWh result (the default is 5). Two to three decimals suit energy bills and appliance estimates; four or more suit engineering records. Watt-hours, joules, and other units use fixed, sensible precision.
Review & Download PDF
See your energy in kilowatt-hours, watt-hours, kWh-and-Wh, joules, kilojoules, megajoules, therms, and kilocalories, plus a chart comparing the numbers. Click Download PDF for a two-page branded report with every conversion, the chart, and a highlighted reference table.
Why 1 kWh = 3,412.14 BTU
The British thermal unit was defined as the heat needed to raise the temperature of one pound of water by one degree Fahrenheit — roughly the heat from burning one wooden kitchen match. Because water’s heat capacity varies slightly with temperature, several BTU definitions grew up. The one used most widely today, and in this calculator, is the International Table (IT) BTU, fixed at exactly 1,055.05585262 joules. Other variants differ by only about 0.1%.
The kilowatt-hour is the energy used by a 1,000-watt load running for one hour. Since a watt is one joule per second, 1 kWh = 1,000 × 3,600 = exactly 3,600,000 joules (3.6 MJ). Dividing one by the other gives 1 kWh = 3,412.14163 BTU and 1 BTU = 0.29307107 Wh. The calculator uses these defined constants internally, so there is no rounding drift.
BTU vs BTU per hour — the most common mix-up
BTU and kWh are both amounts of energy. But the “BTU” on an air conditioner, heater, or furnace label is almost always BTU per hour — a rate, like watts or kilowatts:
- Energy — BTU, kWh, therms, joules. What you’re billed for.
- Power (rate) — BTU/h, kW, watts, tons of cooling. How fast equipment moves heat.
- The link — the same factor converts both: 12,000 BTU/h = 3.517 kW, and running for 1 hour delivers 12,000 BTU = 3.517 kWh.
Just as important, an air conditioner or heat pump’s BTU rating is heat moved, not electricity used. A 12,000 BTU/h AC might draw only about 1,000–1,200 W, because it pumps heat rather than creating it. To turn a BTU rating into electricity use, you also need the unit’s efficiency (EER, SEER, or COP) — covered in the next section.
What the BTU to kWh Converter Calculates
More than a single kWh figure — the tool gives you a complete energy breakdown across electrical, thermal, and SI units, formatted for energy bills, HVAC specs, audits, or reports.
Kilowatt-Hours (Hero Result)
The headline result multiplies your BTU by 0.00029307107 and shows it at the precision you select, with a summary line beneath it that also gives watt-hours and the kWh-and-Wh split — the same unit as your electric bill.
Watt-Hours
Watt-hours (BTU × 0.29307) are how batteries, power stations, and small appliances express energy. They’re handy for smaller BTU values, where a kWh figure would be a long decimal.
kWh & Wh (Composite)
The result is split into whole kilowatt-hours plus leftover watt-hours — 10,000 BTU becomes 2 kWh 931 Wh. That’s an easy way to read a value against a meter reading or battery capacity.
Joules, Kilojoules & Megajoules
The SI energy units — joules (BTU × 1,055.06), kilojoules, and megajoules — appear in engineering specs, international product data, and science coursework, so you can match any metric document.
Therms & Kilocalories
US therms (BTU ÷ 100,000) are the unit on most natural gas bills, so you can compare gas and electric energy directly. Kilocalories (BTU × 0.2522) round out the list for food-energy and science comparisons.
Chart, Reference Table & PDF
A log-scale bar chart compares your value in BTU, kWh, Wh, kJ, and kcal so very different magnitudes fit on one view. A reference table of common HVAC and energy values highlights your input when it matches, and the two-page PDF bundles everything for sharing or record-keeping.
BTU to kWh Conversion Chart — Common Values
Bookmark this page or screenshot the table below for instant reference. Every value uses the IT BTU (1 BTU = 1,055.05585262 J), rounded to four decimals for kWh and megajoules. HVAC rows show the energy delivered in one hour at full rated output — heat moved, not electricity used.
| BTU | Kilowatt-Hours | Watt-Hours | Megajoules | Common Use |
|---|---|---|---|---|
| 1 BTU | 0.000293 kWh | 0.29 Wh | 0.0011 MJ | Roughly one kitchen match |
| 3,412.14 BTU | 1.0000 kWh | 1,000.00 Wh | 3.6000 MJ | Exactly 1 kilowatt-hour |
| 5,000 BTU | 1.4654 kWh | 1,465.36 Wh | 5.2753 MJ | Small window AC, 1 hour |
| 5,118.21 BTU | 1.5000 kWh | 1,500.00 Wh | 5.4000 MJ | 1,500 W space heater, 1 hour |
| 8,000 BTU | 2.3446 kWh | 2,344.57 Wh | 8.4404 MJ | Mid-size window AC, 1 hour |
| 10,000 BTU | 2.9307 kWh | 2,930.71 Wh | 10.5506 MJ | Large window AC, 1 hour |
| 12,000 BTU | 3.5169 kWh | 3,516.85 Wh | 12.6607 MJ | 1 ton of cooling, 1 hour |
| 18,000 BTU | 5.2753 kWh | 5,275.28 Wh | 18.9910 MJ | 1.5-ton AC or mini-split, 1 hour |
| 24,000 BTU | 7.0337 kWh | 7,033.71 Wh | 25.3213 MJ | 2-ton AC, 1 hour |
| 36,000 BTU | 10.5506 kWh | 10,550.56 Wh | 37.9820 MJ | 3-ton central AC, 1 hour |
| 60,000 BTU | 17.5843 kWh | 17,584.26 Wh | 63.3034 MJ | 5-ton central AC, 1 hour |
| 80,000 BTU | 23.4457 kWh | 23,445.69 Wh | 84.4045 MJ | 80,000 BTU/h furnace input, 1 hour |
| 100,000 BTU | 29.3071 kWh | 29,307.11 Wh | 105.5056 MJ | 1 therm of natural gas |
| 1,000,000 BTU | 293.0711 kWh | 293,071.07 Wh | 1,055.0559 MJ | 1 MMBtu (dekatherm) |
How to Use BTU Ratings and Compare Gas vs Electric Costs
The most common reasons people convert BTU to kWh are to estimate what an air conditioner or heater will cost to run, and to compare gas heating (billed in therms) with electric heating (billed in kWh). Both need the unit conversion and the equipment’s efficiency.
The manual calculation
Step 1: Multiply the BTU/h rating by the hours of operation to get BTU. Step 2: Divide by 3,412.14 for kWh of heating or cooling delivered. Step 3: For electricity used, divide the BTU/h rating by the EER to get watts. For a 24,000 BTU/h mini-split (EER 12) running 6 hours at full output:
144,000 BTU ÷ 3,412.14 = 42.2022 kWh of cooling (42 kWh 202 Wh)
Electricity: 24,000 ÷ 12 = 2,000 W × 6 h = 12 kWh
Result: about 42.2 kWh of cooling for about 12 kWh of electricity
Enter the BTU figure in the calculator and it does the first two steps for you. The gap between cooling delivered and electricity used is the unit’s efficiency at work — an EER of 12 is equivalent to a COP of about 3.5. Real-world use varies with cycling, outdoor temperature, and thermostat settings.
Comparing a price per therm with a price per kWh
Gas is billed per therm (100,000 BTU) and electricity per kWh (3,412 BTU), so convert to the same unit before comparing — then account for efficiency:
- Price per kWh-equivalent = price per therm ÷ 29.3071
- Price per therm-equivalent = price per kWh × 29.3071
- Example: gas at $1.50 per therm ≈ $0.0512 per kWh of energy; at 95% furnace efficiency, about $0.054 per kWh of heat
- Example: electricity at $0.16 per kWh ≈ $4.69 per therm; a heat pump with a COP of 3 delivers heat for about $0.053 per kWh
BTU to kWh — Key Conversion Numbers
The BTU to kWh Converter Is Built For You If…
Whether you’re sizing an air conditioner, comparing gas and electric heat, or reading a home’s utility costs — this calculator gives you the exact answer in seconds, with a report you can save and share.
Homeowners & Renters
AC, heating & energy billsAir conditioners, space heaters, furnaces, and water heaters are rated in BTU, while your electric bill is in kWh and your gas bill in therms. Converting helps you understand equipment ratings, estimate running costs, and compare heating options on the same scale.
- Appliance “BTU” ratings are usually BTU per hour
- Use EER or wattage — not BTU — for electricity use
- 1 therm of gas = about 29.3 kWh of energy
- Compare cost of heat delivered, not energy bought
HVAC Pros & Energy Auditors
Loads, specs & auditsContractors and auditors move between equipment ratings in BTU/h and tons, heat-pump specs in kW and COP, utility data in therms and kWh, and international product sheets in joules. An exact converter with a printable report keeps proposals and audit reports consistent.
- 1 ton = 12,000 BTU/h ≈ 3.517 kW
- COP ≈ EER ÷ 3.412
- Label figures as BTU or BTU/h on every proposal
- Attach the PDF to show the factor used
Homebuyers & Solar Shoppers
Utility costs & electrificationListings and inspections describe furnaces and water heaters in BTU, while solar proposals, batteries, and EV chargers use kWh. Converting helps you estimate a home’s heating load in solar terms and judge what switching from gas to a heat pump might mean for your bills.
- Convert annual gas use (therms × 29.3071) to kWh
- Divide heating kWh by heat-pump COP for electricity needed
- Ask for 12 months of utility bills before buying
- Use 1–2 decimals — estimates aren’t more precise
7 Tips for Accurate BTU to kWh Conversions
The conversion is fixed, but the ratings around it are easy to misread. Most mistakes come from mixing up energy and power, ignoring efficiency, rounding factors, and comparing prices in different units. These rules keep every conversion trustworthy.
Tell BTU From BTU per Hour
A BTU is energy; BTU/h is a rate. Equipment ratings are BTU/h — multiply by hours of operation to get BTU before converting to kWh, or convert BTU/h straight to kW with the same factor.
Output Is Not Input
An AC or heat pump’s BTU rating is heat moved, not electricity used. Divide the BTU/h rating by the EER to estimate watts, or divide delivered kWh by the COP. For gas equipment, multiply input BTU by the AFUE for useful heat.
Compare Prices in the Same Unit
Divide a price per therm by 29.3071 to compare it with a price per kWh. Then divide each by the equipment’s efficiency to get the cost of heat actually delivered — that’s the number that matters.
Don’t Round 0.000293 to 0.0003
Multiplying BTU by 0.0003 overstates kWh by about 2.4%. That’s fine for a rough idea, but on annual heating of 60 million BTU it adds over 400 kWh. Use 3,412.14 or the calculator for bills and audits.
Remember 1 Ton = 12,000 BTU/h
AC and heat-pump sizes are often given in tons. One ton is 12,000 BTU/h, or about 3.517 kW of cooling. A “3-ton” system is 36,000 BTU/h — about 10.55 kW of heat moved, not 10.55 kW of electricity drawn.
Read Your Gas Bill Carefully
Gas meters measure volume (often in CCF, or hundreds of cubic feet), and utilities convert that to therms using a heat-content factor printed on the bill. Use the therm figure — not the CCF figure — when converting to kWh.
Memorize Three Anchors for Mental Math
1 kWh ≈ 3,412 BTU. 1 therm ≈ 29.3 kWh. 1 ton = 12,000 BTU/h ≈ 3.5 kW. With these you can sanity-check any spec in your head — a 1,500 W space heater gives about 5,100 BTU/h, and 10 therms is about 293 kWh.
BTU to kWh Converter — Frequently Asked Questions
Everything you need to know about converting BTU to kilowatt-hours, the difference between BTU and BTU per hour, and how to apply this calculator to air conditioners, heaters, gas bills, and energy costs.
One BTU equals about 0.000293071 kilowatt-hours, or 0.2931 watt-hours. This uses the International Table BTU, defined as 1,055.05585262 joules, and the kilowatt-hour, which is exactly 3,600,000 joules. Put the other way, 1 kWh = 3,412.14 BTU.
Divide BTU by 3,412.14163: kWh = BTU ÷ 3,412.14163, which is the same as kWh = BTU × 0.00029307107. For example, 10,000 BTU ÷ 3,412.14 = 2.9307 kWh, 12,000 BTU = 3.5169 kWh, and 100,000 BTU (1 therm) = 29.3071 kWh. To go from kWh back to BTU, multiply by 3,412.14163.
One kilowatt-hour equals about 3,412.14 BTU. To convert kWh to BTU, multiply by 3,412.14163. For example: 1 kWh = 3,412.14 BTU, 5 kWh = 17,060.71 BTU, 10 kWh = 34,121.42 BTU, and 30 kWh = 102,364.25 BTU. This converter takes BTU as its input; to check a result, enter the BTU figure you calculated and confirm the kWh result matches.
A BTU is an amount of energy, like a kWh. BTU per hour (BTU/h) is a rate of energy, like a kilowatt. Air conditioner, heater, and furnace ratings such as 12,000 BTU are really BTU per hour. A 12,000 BTU/h air conditioner delivers about 3.517 kW of cooling, or 3.517 kWh of cooling for every hour it runs at full output. That cooling output is not the same as the electricity it uses.
It depends on efficiency. Electrical draw in watts is roughly the BTU/h rating divided by the EER (energy efficiency ratio). A 12,000 BTU/h unit with an EER of 10 draws about 1,200 W, or 1.2 kWh per hour at full output; with an EER of 12 it draws about 1,000 W, or 1 kWh per hour. Real use varies with cycling, outdoor temperature, and thermostat settings, so check the unit’s label or EnergyGuide for its rated wattage.
One US therm is 100,000 BTU, which equals about 29.3071 kWh. One dekatherm or MMBtu (1,000,000 BTU) equals about 293.0711 kWh. These are energy-content equivalents; the useful heat you get depends on the efficiency of the appliance burning the gas.
Divide the price per therm by 29.3071 to get a price per kWh of energy content. For example, gas at $1.50 per therm is about $0.0512 per kWh-equivalent. Then adjust for efficiency: a 95% efficient furnace delivers heat for about $0.054 per kWh, while a heat pump with a COP of 3 running on $0.16 per kWh electricity delivers heat for about $0.053 per kWh. Electric resistance heat at the same rate costs the full $0.16 per kWh of heat.
One ton of cooling is 12,000 BTU per hour, or about 3.517 kW. The term comes from the heat needed to melt one short ton of ice over 24 hours. A 2-ton air conditioner is 24,000 BTU/h (about 7.03 kW), a 3-ton unit is 36,000 BTU/h (about 10.55 kW), and a 5-ton unit is 60,000 BTU/h (about 17.58 kW).
Electric resistance heaters turn essentially all of the electricity they use into heat, so 1 kWh of electricity gives about 3,412 BTU of heat. A 1,500-watt space heater produces about 5,118 BTU per hour and uses 1.5 kWh for each hour it runs on high.
A British thermal unit is the heat needed to raise the temperature of one pound of water by one degree Fahrenheit — roughly the heat from burning one wooden kitchen match. Several slightly different BTU definitions exist; this converter uses the International Table BTU of 1,055.05585262 joules, the most widely used definition. Other variants differ by about 0.1%.
One BTU equals about 1,055.06 joules, 1.0551 kilojoules, or 0.2522 kilocalories (food Calories). One kilowatt-hour equals exactly 3.6 megajoules, or about 860.42 kilocalories.
The converter uses defined constants: 1 BTU (IT) = 1,055.05585262 J; 1 kWh = 3,600,000 J; 1 US therm = 100,000 BTU; and 1 kcal = 4,184 J. Calculations use double-precision floating-point arithmetic, accurate to about 15 significant digits, and display precision is adjustable from 0 to 8 decimal places. In practice, accuracy is limited by the rating or estimate you start with and by equipment efficiency, not by the conversion.
Accuracy note: The HomeExpertly BTU to kWh Converter uses the International Table BTU: 1 BTU = 1,055.05585262 joules, together with 1 kWh = 3,600,000 joules, so 1 kWh = 3,412.14163 BTU. It also uses 1 US therm = 100,000 BTU and 1 kilocalorie = 4,184 joules. Other BTU definitions (such as the thermochemical BTU) differ by about 0.1%. All calculations are mathematically precise to the decimal precision you select (up to 8 places). However, results are for informational and reference purposes only. Equipment ratings are usually in BTU per hour and describe heat output or input, not electricity consumption; actual energy use depends on efficiency ratings (EER, SEER, COP, HSPF, AFUE), climate, installation, and usage. Example prices, efficiencies, and appliance figures on this page are illustrative and vary by product, utility, and region. For applications where energy figures are critical — including but not limited to HVAC sizing and load calculations, equipment selection, energy audits, utility or rebate filings, solar and battery sizing, or contract pricing — always verify figures independently using manufacturer specifications, your actual utility bills, and a qualified HVAC or energy professional. HomeExpertly is not responsible for any consequences arising from the use of these conversions, including but not limited to undersized or oversized equipment, unexpected energy costs, or billing disputes.