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Convert energy units between watt-hours and joules with real-time bidirectional conversion.
1 watt-hour = 3600 joules
joules = watt-hours × 3600
Note: 1000 Wh = 1 kWh = 3.6 MJ
| Watt-Hours (Wh) | Joules (J) |
|---|---|
| 0.1 | 360 |
| 0.5 | 1,800 |
| 1 | 3,600 |
| 5 | 18,000 |
| 10 | 36,000 |
| 20 | 72,000 |
| 50 | 180,000 |
| 100 | 360,000 |
| 500 | 1,800,000 |
| 1,000 | 3,600,000 |
| 5,000 | 18,000,000 |
| 10,000 | 36,000,000 |
A watt-hour (Wh) is a unit of energy equal to one watt of power sustained for one hour. It's commonly used to measure battery capacity in portable electronics, electric vehicles, and solar energy systems. For example, a 10 Wh battery can provide 10 watts of power for 1 hour, or 5 watts for 2 hours, or 1 watt for 10 hours.
Batteries are typically rated in watt-hours or milliwatt-hours (mWh). A smartphone battery might be rated at 15 Wh (15,000 mWh), while an electric car battery could be 60,000 Wh (60 kWh). Understanding watt-hours helps you compare battery capacities and estimate device runtime. Higher watt-hour ratings mean longer operation times or more stored energy.
The conversion factor comes from the definition of power and energy. Since 1 watt = 1 joule per second, and 1 hour = 3600 seconds, then 1 watt-hour = 1 watt × 3600 seconds = 3600 joules. This relationship connects power (rate of energy use) with energy (total amount). It's the same principle that gives us the kWh to joules conversion (1 kWh = 3,600,000 J).
While watt-hours are practical for describing battery capacity and electricity consumption, joules are fundamental in physics equations. Converting between these units is essential in energy calculations, electrical engineering, and when designing power systems. Understanding both units allows engineers to work with practical specifications while maintaining scientific accuracy.
To convert watt-hours to joules, multiply the Wh value by 3600. For example, 5 Wh = 5 × 3600 = 18,000 joules. This works because there are 3600 seconds in an hour, and 1 watt = 1 joule/second.
Watts (W) measure power (energy per unit time), while watt-hours (Wh) measure energy (total amount). Think of watts as speed and watt-hours as distance. A 60W light bulb running for 2 hours uses 120 Wh of energy. Power tells you the rate; energy tells you the total amount consumed.
Modern smartphone batteries range from about 10-20 Wh (10,000-20,000 mWh). For example, an iPhone might have a 3000 mAh battery at 3.8V, which equals approximately 11.4 Wh. Tablet batteries are larger, typically 20-40 Wh, while laptop batteries range from 40-100 Wh.
Divide the battery capacity in watt-hours by the device's power consumption in watts. For example, a 20 Wh battery powering a 5W device will last approximately 4 hours (20 Wh ÷ 5 W = 4 h). This is an estimate; actual runtime depends on efficiency and usage patterns.