Enter a power rate
Use BTU per hour (BTU/hr or BTUH) for a direct conversion to watts. A standalone BTU value is energy and needs a time period.
Instant, accurate energy conversion
Convert BTU to Watts in real time
A clean, no-nonsense calculator for HVAC, heating, and cooling power. Convert between BTU/hr, watts, kilowatts, tons of refrigeration, and horsepower — with the formula explained.
BTU/hr↔ Watts↔ kW · RT · hp
BTU/hr
Accepts zero, positive values, decimals, and either a dot or comma decimal separator.
3,516.85W
Also equals
Kilowatts
3.5169 kW
Tons (RT)
1 RT
Horsepower
4.7162 hp
kcal/hr
3,025.97 kcal/hr
Calculator guide
How to use the BTU to watts calculator
Confirm the source unit before entering a value. HVAC labels often shorten BTU/hr to BTU, but watts require a rate of energy transfer.
Read thermal watts
The result is the equivalent heat-transfer rate in watts. Round the final answer to the precision your task requires.
Reverse when needed
Switch the converter direction to change watts back to BTU/hr. One watt equals approximately 3.412142 BTU/hr.
What the result cannot determine
A conversion does not know equipment efficiency, rated electrical input, voltage, current, startup surge, runtime, thermostat cycling, climate, insulation, or installation quality. Use the equipment nameplate and manufacturer data for electricity use, circuits, generators, batteries, or solar-system planning.
Live visualization
Watch the conversion happen
Each particle represents a slice of energy flowing from BTU/hr on the left, through the conversion factor, to watts on the right. Drag the slider — more BTU/hr means denser flow.
12,000
BTU/hr
3,516.85
Watts
12,000 BTU/hr
Quick fill:
Fundamentals
What is BTU to Watts?
BTU to Watts is a power conversion from British Thermal Unit per hour (BTU/hr) to watts (W). One BTU equals 1,055.05585 joules (J), and one hour equals 3,600 seconds, which fixes the exchange rate at 1 BTU/hr = 0.29307107 W. The conversion links the Imperial System to the International System of Units (SI).
What is a BTU?
A British Thermal Unit (BTU) is the energy needed to raise one pound of water by one degree Fahrenheit. Equipment specs use BTU/hr — the rate at which an AC removes heat or a heater delivers it.
HVAC equipment uses BTU/hr because U.S. industry grew up around the Imperial System. In physics, it measures the same quantity as a watt — power.
What is a Watt?
A watt (W) is the SI unit of power — one joule (J) per second. Watts appear on every light bulb, appliance, power supply, and electricity bill, which makes it the common language for power draw and heat output.
Kilowatts (kW), megawatts (MW), and milliwatts (mW) are the same unit scaled by 1,000.
How they relate
BTU/hr and watts both measure a rate of energy, so converting between them is a single multiplication. The fixed exchange rate is 1 BTU/hr = 0.29307107 W.
- •Cooling capacity sizing in HVAC
- •Heater output translation
- •Electric power comparison
The formula
BTU to Watts formula
The BTU to Watts formula is P(W) = P(BTU/hr) × 0.29307107. The equivalent division form is P(W) = P(BTU/hr) / 3.412141633. P stands for power. The multiplier is fixed by the BTU definition (1,055.05585 joules) divided by 3,600 seconds per hour.
BTU/hr → Watts
P(W) = P(BTU/hr) × 0.29307107
Multiply BTU/hr by 0.29307107 to get watts.
Watts → BTU/hr
P(BTU/hr) = P(W) × 3.41214163
Going the other way, multiply watts by 3.41214163.
Worked example
Convert a 12,000 BTU/hr one-ton air conditioner to watts:
1Start
12,000 BTU/hr
2Multiply
12,000 × 0.29307107
3Result
≈ 3,516.85 W
The same value equals 3.517 kW, 1 ton of refrigeration (RT), and about 4.716 horsepower (hp). Cooling capacity is the quantity here — electrical draw depends on efficiency (SEER/EER) separately.
Power explorer
Drag to see BTU/hr across every power unit
1-ton AC
BTU per hour
12,000
BTU/hr
→
Watts
3,516.85
W
Kilowatts
3.5169 kW
Tons (RT)
1 RT
Horsepower
4.7162 hp
Heat intensity
20 %
How to Convert BTU to Watts
To convert BTU to watts, multiply the power in BTU/hr by 0.29307107. Three steps complete the conversion:
01
Read the BTU/hr value
Take the power in BTU/hr from the equipment spec label, product sheet, or manufacturer page.
02
Multiply by 0.29307107
Apply the fixed conversion factor. Dividing by 3.412141633 returns the same result.
03
Record in watts
Use watts (W) for electrical comparison, kilowatts (kW) for larger systems, or tons for HVAC sizing.
Example: a 5,000 BTU/hr window unit converts to 5,000 × 0.29307107 = 1,465.36 W (1.465 kW). A 15,000 BTU/hr unit converts to 4,396.07 W (4.396 kW).
Reference
BTU to Watts conversion table
This conversion table lists power in BTU/hr and the equivalent power in watts (W) and kilowatts (kW) at the fixed ratio 0.29307107. Values cover 1 BTU/hr through 100,000 BTU/hr, matching the range most residential, commercial, and industrial HVAC calculations need.
| Power (BTU/hr) | Power (W) | Power (kW) | Typical use |
|---|---|---|---|
| 1 BTU/hr | 0.293071 W | 0.000293 kW | — |
| 10 BTU/hr | 2.9307 W | 0.002931 kW | — |
| 100 BTU/hr | 29.3071 W | 0.029307 kW | — |
| 500 BTU/hr | 146.54 W | 0.146536 kW | — |
| 1,000 BTU/hr | 293.07 W | 0.293071 kW | Small space heater |
| 2,000 BTU/hr | 586.14 W | 0.586142 kW | — |
| 5,000 BTU/hr | 1,465.36 W | 1.4654 kW | Window AC (small room) |
| 8,000 BTU/hr | 2,344.57 W | 2.3446 kW | Window AC (medium room) |
| 10,000 BTU/hr | 2,930.71 W | 2.9307 kW | Portable AC |
| 12,000 BTU/hr | 3,516.85 W | 3.5169 kW | 1-ton AC unit |
| 15,000 BTU/hr | 4,396.07 W | 4.3961 kW | Mid-size AC |
| 18,000 BTU/hr | 5,275.28 W | 5.2753 kW | 1.5-ton AC unit |
| 24,000 BTU/hr | 7,033.71 W | 7.0337 kW | 2-ton AC unit |
| 36,000 BTU/hr | 10,550.56 W | 10.5506 kW | 3-ton central AC |
| 50,000 BTU/hr | 14,653.55 W | 14.6536 kW | — |
| 60,000 BTU/hr | 17,584.26 W | 17.5843 kW | 5-ton central AC |
| 100,000 BTU/hr | 29,307.11 W | 29.3071 kW | — |
Compare
Watts vs BTU: key differences
BTU and watts measure related but distinct quantities. The sections below cover the difference, the 1-to-1 rate that links them, and whether they represent the same thing.
Unit parity
One value, two scales
ratio 1 : 0.29307
0
2k
4k
6k
8k
10k
12k
6,000 ≡ 1,758.43
BTU/hr ≡ W
0
500
1k
1.5k
2k
2.5k
3k
3.5k
BTU/hrW
Drag the slider. Both rulers are aligned so the same physical position shows BTU/hr on top and watts on bottom — visual proof that 1 BTU/hr equals 0.29307107 W.
What's the difference between Watts and BTUs?
Watts (W) measure power in the International System of Units (SI), and BTU (British Thermal Unit) measures energy in the Imperial System. Three differences separate the two:
- Unit system: watts belong to SI; BTU belongs to the Imperial System.
- Quantity type: BTU measures energy (joules); watts measure power (joules per second); BTU/hr measures power (energy per hour).
- Typical use: watts appear on electrical ratings, power supplies, and lighting; BTU/hr appears on HVAC equipment, gas appliances, and heaters.
Both relate through 1 BTU/hr = 0.29307107 W, which lets one equipment label translate across electric power, kW, MW, hp, and dBm comparisons.
How many BTU in Watts?
1 watt (W) equals 3.412141633 BTU per hour (BTU/hr). Five common values:
- 1 W = 3.412142 BTU/hr
- 10 W = 34.121416 BTU/hr
- 100 W = 341.214163 BTU/hr
- 1,000 W (1 kW) = 3,412.14 BTU/hr
- 1,000,000 W (1 MW) = 3,412,141.63 BTU/hr
The reverse direction uses P(BTU/hr) = P(W) × 3.412141633.
Is BTU the same as Watts?
No, BTU is not the same as watts. BTU measures energy (about 1,055.05585 joules), and watts measure power (1 joule per second). BTU/hr, which is the form seen on equipment labels, measures a rate of energy transfer and maps 1-to-1 with watts at 0.29307107 W per BTU/hr.
In short: BTU is an energy quantity, watts is a power quantity, and BTU/hr is a power quantity that aligns directly with watts.
Application
Sizing a room by BTU and watts
The most common real-world use of BTU to watts conversion is HVAC sizing. A rough rule of 20 BTU/hr per ft² covers moderate climates, with climate and exposure shifting the factor up or down.
Room sizer
Match room size to BTU and watts
16 × 12 ft16 ft12 ft
Length16 ft
Width12 ft
Area192 ft²
Recommended BTU/hr
4,224
Equivalent watts
1,237.93 W
In kilowatts
1.2379 kW
Uses a simple rule of 22 BTU/hr per ft² for a moderate climate. Real sizing also factors ceiling height, insulation, sun exposure, and occupancy.
Scope
Limitations and assumptions
This calculator converts the entered quantities using fixed unit relationships. It does not estimate equipment efficiency, electrical consumption, operating cost, installation losses, safety margins, or local code requirements.
Treat the result as a unit conversion or planning estimate. Verify safety-critical sizing and equipment decisions against manufacturer data and qualified professional guidance.
Questions
Frequently Asked Questions
Direct answers to common BTU, watts, HVAC capacity, and room-sizing questions.
Related tools
More power converters
Dedicated pages for each conversion pair, with a live calculator, formula, table, and FAQ.
BTU/hr to kW
Convert to kilowatts for metric and European spec sheets.
BTU/hr to MW
Megawatt output for industrial chillers and power plants.
KVA to BTU/hr
Apparent power to heat output, with power factor.
BTU/hr to Horsepower
Thermal power in mechanical hp for motor sizing.
BTU/hr to kcal/hr
Metric calorie-based HVAC spec conversion.
BTU/hr to MBH
Commercial HVAC schedules and boiler plate ratings.
BTU/s to Watts
Per-second heat-transfer rate to SI watts.
BTU/hr to Tons
Cooling capacity from BTU/hr nameplate to contractor tonnage.
BTU/min to Watts
Bench-test minute-rate heat flux to SI watts.
BTU/day to Watts
Daily heat-gain budgets to steady-state watts.
BTU to kWh
Energy quantity for gas-vs-electric cost comparisons.
BTU to Joules
Exact SI energy conversion for physics and chemistry.
BTU to kJ
Engineering and food-science energy in kilojoules.
BTU to MMBTU
Million-BTU for natural gas contracts and trading.
BTU to Therms
100,000-BTU units for residential gas bills.
BTU to Wh
Watt-hours for battery and small-device equivalence.
BTU/lb to Watts
Combustion power from fuel heating value and mass flow.
Trust and accuracy
Methodology and accuracy
Calculations retain JavaScript numeric precision internally and round only the displayed result. Fixed conversion constants and the review process are documented on our calculator methodology page.
For adjacent intent, use the broader BTU to watts converter, review the conversion formula guide, or check common values in the BTU to watts chart.
Last reviewed: August 7, 2026
Calculator summary
The BTU to watts calculator converts compatible power units instantly while preserving full internal precision. Use BTU/hr—not a standalone BTU energy quantity—for a direct watts conversion, and do not treat equivalent thermal watts as automatic appliance electricity consumption.