How many joules is 1 BTU?

1 BTU (IT) equals exactly 1055.05585262 joules. This is the International Table BTU, the most common definition used in engineering and commerce. Another variant, the thermochemical BTU, equals 1054.3503 J, but the IT value is standard.

How do I convert BTU to joules manually?

Multiply the BTU value by 1055.05585. For example, 5 BTU × 1055.05585 = 5275.28 J. To convert joules back to BTU, divide by 1055.05585 (or multiply by approximately 0.000947817).

What is the difference between BTU and joule?

The joule (J) is the SI unit of energy, defined as the work done by a force of one newton over one metre. The BTU (British Thermal Unit) is an imperial unit defined as the energy needed to raise one pound of water by 1 °F at its maximum density. BTU is common in heating, cooling, and energy industries in the US, while joule is used globally in science and most engineering.

How many BTU is 1000 joules?

1000 joules ÷ 1055.05585 = approximately 0.9478 BTU. For rough estimates, 1 kJ ≈ 0.948 BTU.

What is BTU/h and how does it relate to watts?

BTU/h (BTU per hour) is a unit of power, not energy. 1 BTU/h = 1055.05585 J / 3600 s ≈ 0.29307 watts. Air conditioner ratings are often given in BTU/h — divide by 3.412 to convert to watts.

Why is BTU still used instead of joules?

BTU persists in industries — especially HVAC, gas utilities, and food energy in the US — due to historical convention and existing equipment ratings. The joule is used everywhere else. Both units represent the same physical quantity; the BTU is simply a larger unit (about 1055 times larger than 1 joule).

BTU to Joules Converter

Name: BTU to Joules Converter
Availability: InStock
Author: Nham Vu

Enter a value in BTU and get the joule equivalent instantly, with reverse joules-to-BTU conversion and a common reference table.

Converter

Energy in BTU (British Thermal Units)

Result in joules (J)

Reverse: joules to BTU

Energy in joules (J)

Result in BTU

Reference Table

BTU Joules (J)

0.1 BTU 105.506

0.5 BTU 527.528

1 BTU 1,055.06

2 BTU 2,110.11

5 BTU 5,275.28

10 BTU 10,550.6

20 BTU 21,101.1

50 BTU 52,752.8

100 BTU 105,506

500 BTU 527,528

1,000 BTU 1,055,056

10,000 BTU 10,550,559

Formula: J = BTU × 1055.05585 • BTU = J ÷ 1055.05585

Summary

Enter a value in BTU and get the joule equivalent instantly, with reverse joules-to-BTU conversion and a common reference table.

How it works

Enter an energy value in BTU in the top input field.
The joule result appears instantly — no button press needed.
Use the reverse field to convert joules back to BTU.
Click "Copy" next to any result to copy the value to your clipboard.
Check the reference table for common BTU-to-joule values at a glance.

Use cases

Convert heating or cooling loads from BTU to joules for SI-unit engineering specs.
Translate HVAC capacity ratings from BTU/h to watts (joules per second) for metric countries.
Convert food calorie equivalents to joules when comparing energy content in nutrition data.
Cross-check furnace or boiler output in BTU against joule-based efficiency calculations.
Convert natural gas energy content from BTU to joules for billing or combustion analysis.
Translate air-conditioner BTU ratings to joules for international product comparisons.
Convert scientific experiment energy values from BTU to the SI unit (joule) for publication.
Verify heat transfer calculations that mix imperial BTU and metric joule data.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu