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Watt-hours to Joules Converter

Enter the energy in watt-hours below to convert it to joules.

Convert Watt-hours to Joules

Enter a value in watt-hours (Wh) to convert to joules (J).

Result
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18,000joules
5 Wh = 18,000 J
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Suggested Conversions
Reference:NIST CODATA (CODATA Energy & Thermodynamic Constants)
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Watt-hour to Joule Conversion Table

Table showing various watt-hour measurements converted to joules. Click any preset value or arrow to load it into the converter.

Watt-hours (Wh)Joules (J)
1 Wh3,600 J
2 Wh7,200 J
2.5 Wh9,000 J
5 Wh18,000 J
10 Wh36,000 J
15 Wh54,000 J
20 Wh72,000 J
25 Wh90,000 J
30 Wh108,000 J
50 Wh180,000 J

How to Convert Watt-hours to Joules

To convert watt-hours to joules, multiply the energy by the following conversion ratio: 3,600 joules/watt-hour.

Since one watt-hour is equal to 3,600 joules, you can use this simple formula to convert:

joules = watt-hours × 3,600

The energy in joules is equal to the energy in watt-hours multiplied by 3,600.

For example, here's how to convert 5 watt-hours to joules using the formula above.

joules = (5 Wh × 3,600) = 18,000 J

How Many Joules Are in a Watt-hour?

There are 3,600 joules in a watt-hour, which is why we use this value in the formula above.

1 Wh = 3,600 J|1 J = 0.000277778 Wh

Our watt-hour to joule calculator automatically converts your energy measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.

Watt-hours and joules are both units used to measure energy. Keep reading to learn more about each unit.

What Is a Watt-hour?

A watt-hour is a unit of energy equal to 3,600 joules (J), the base unit for energy. Equal to 3,600 Joules. [1]

The watt-hour is classified as a metric and SI-compatible unit of energy. Watt-hours can be abbreviated as Wh; for example, 1 watt-hour can be written as 1 Wh.

When working with watt-hours (Wh) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.

In practice, watt-hours (Wh) are widely used across large-scale industrial, bulk, and macro-level energy specifications within SI metric workflows, engineering documentation, and technical data sheets.

What Is a Joule?

Coherent SI unit of energy and work (1 W·s = 1 N·m). It serves as a primary reference unit for measuring energy across scientific and practical applications. [2]

The joule is classified as an International System of Units (SI) unit of energy. Joules can be abbreviated as J; for example, 1 joule can be written as 1 J.

As the primary coherent reference unit for energy in this category, all other energy units are mathematically anchored to the joule (J).

In practice, joules (J) are widely used across standard energy applications within International System of Units (SI) workflows, engineering documentation, and technical data sheets.

When converting energy between watt-hours (Wh) and joules (J), keep full floating-point precision (1 Wh = 3,600 J; 1 J = 0.000277778 Wh) during intermediate calculations and round only the final joule figure to match your instrument tolerance.

More Watt-hour & Joule Conversions

Need to calculate in the opposite direction? Use our joules to watt-hours calculator to switch your starting unit immediately. You can also explore related tools such as converting joules to watt-hours, converting calories to joules, or converting kilojoules to joules.

Frequently Asked Questions

There are 3,600 joules (J) in 1 watt-hour (Wh). Conversely, 1 joule (J) is equal to 0.00027777 watt-hours (Wh).

References

NIST · BIPM · ISO
  1. [1]
    NIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Watt-hours (Wh) to Joules (J)
    NIST CODATA Standard
  2. [2]
    NIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Watt-hour (Wh) & Joule (J)
    NIST SP 811 Specification
  3. [3]
    BIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (Wh to J)
    BIPM Reference
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