W to kWh Calculator
Convert power in watts (W) to energy in kilowatt-hours (kWh) using time in hours. This tool helps you estimate electricity consumption for any appliance or device.
Understanding Watts to Kilowatt-Hours Conversion
Converting from watts (W) to kilowatt-hours (kWh) allows you to estimate the total energy consumed by an electrical device over time. This is essential for understanding electricity bills, appliance efficiency, and generator sizing.
What is a Watt?
A watt is a unit of power. It tells you how fast a device consumes or generates energy. One watt is equal to one joule per second.
What is a Kilowatt-Hour?
A kilowatt-hour (kWh) is a unit of energy. It represents the amount of energy used when a device rated at 1,000 watts runs for one hour.
Conversion Formula
To convert watts to kilowatt-hours, use the following formula:
kWh = (Watts × Hours) ÷ 1000
Example Calculations
- 500 W for 2 hours → kWh = (500 × 2) ÷ 1000 = 1.0 kWh
- 1200 W for 1.5 hours → kWh = (1200 × 1.5) ÷ 1000 = 1.8 kWh
- 60 W for 24 hours → kWh = (60 × 24) ÷ 1000 = 1.44 kWh
Why This Conversion Is Important
Most electricity meters and utility bills measure usage in kWh. Knowing how to convert watts into kWh helps you:
- Understand your electricity bill
- Compare the energy usage of different appliances
- Estimate generator run time or solar battery capacity
- Design energy-efficient systems
Common Household Devices and Their kWh Usage
| Appliance | Power (W) | Time (hours) | Energy (kWh) |
|---|---|---|---|
| Electric kettle | 1500 | 0.25 | 0.375 |
| Desktop computer | 250 | 5 | 1.25 |
| Ceiling fan | 70 | 8 | 0.56 |
| Washing machine | 500 | 1.5 | 0.75 |
Estimating Energy Costs
If you know your electricity rate (cost per kWh), you can estimate the cost of running an appliance:
Cost = kWh × Rate
Example: A 1000W heater running for 3 hours uses 3 kWh. If electricity costs $0.15 per kWh:
- Cost = 3 × 0.15 = $0.45
Frequently Asked Questions
Can I convert watts to kWh without time?
No. Since kWh includes time, you must know how long the device is running.
Is kWh the same as 1000 watts?
No. 1 kWh means 1000 watts used for 1 hour. It includes both power and time.
How much is 1 kWh?
1 kWh is enough energy to power a 1000W device for 1 hour or a 100W lightbulb for 10 hours.
How do I reduce my kWh usage?
Use energy-efficient devices, reduce run time, and unplug appliances when not in use.