Wh to kWh Energy Converter
Convert stored energy between watt-hours, kilowatt-hours, joules and BTU. Compare battery capacities, calculate power station runtime, or understand your electricity bill.
Last updated: May 2026
Enter a value to see the conversion instantly.
How to use this energy converter
Type the battery capacity or energy amount, pick your unit, and the result shows up in all other units instantly. The quick buttons cover typical use cases: 100 Wh is a small USB power bank, 500 Wh runs a laptop all day, 1000 Wh (1 kWh) is a mid-size portable power station, 10 kWh is a home battery backup or small EV battery.
Common energy reference values
| Application | Wh | kWh | Joules | BTU |
|---|---|---|---|---|
| USB power bank | 50-200 Wh | 0.05-0.2 kWh | 180-720 kJ | 171-683 BTU |
| Laptop battery | 40-100 Wh | 0.04-0.1 kWh | 144-360 kJ | 137-341 BTU |
| Portable power station | 500-2000 Wh | 0.5-2 kWh | 1.8-7.2 MJ | 1,706-6,824 BTU |
| E-bike battery | 400-700 Wh | 0.4-0.7 kWh | 1.44-2.52 MJ | 1,365-2,389 BTU |
| Home battery (Powerwall) | 13,500 Wh | 13.5 kWh | 48.6 MJ | 46,063 BTU |
| Small EV battery | 40,000 Wh | 40 kWh | 144 MJ | 136,485 BTU |
| Household daily usage | 10,000-30,000 Wh | 10-30 kWh | 36-108 MJ | 34,121-102,364 BTU |
When you need this tool
Your portable power station lists 512 Wh capacity but you want to know if that's enough to run a 200W fridge during a 6-hour outage. Or you're comparing EV battery packs where one is 40 kWh and another is 64,000 Wh. Or your electricity bill shows usage in kWh but your solar installer talks about batteries in Wh. Convert it here and skip the mental math.
Frequently Asked Questions
When do I need to convert between Wh and kWh?
Battery packs, power stations and electricity meters use different units. A portable power station shows capacity in Wh, your electricity bill shows usage in kWh, and solar installers often mix both. Converting keeps you aligned with whatever spec you're comparing or calculating.
What is the formula?
1 kWh = 1000 Wh. It's a simple scale-up by 1000 units. The other conversions: 1 Wh = 3600 J (joules), and 1 kWh ≈ 3412 BTU.
Why is exact conversion important for batteries?
A power station rated at 512 Wh (which is 0.512 kWh) covers different use cases than 1000 Wh. Runtime, backup duration and real-world use depend on getting the number right. Rounding off battery capacity leads to miscalculating how long a fridge or laptop will run.