kWh Consumption Calculator – Electricity Usage & Cost
Calculate electricity consumption and costs from power usage
Table of Contents
How to Use
- Enter the power rating of your appliance in watts
- Enter the number of hours used per day
- Enter the number of days in the period
- Enter your electricity cost per kWh
- Click calculate to see consumption and costs
What is a Kilowatt-Hour (kWh)?
A kilowatt-hour (kWh) is a unit of energy equal to one kilowatt (1,000 watts) of power sustained for one hour. It's the standard unit used by utility companies to measure and bill for electricity consumption.
For example, a 100-watt light bulb running for 10 hours consumes 1 kWh of electricity (100W × 10h = 1,000Wh = 1kWh).
How to Calculate Energy Consumption
To calculate energy consumption:
- Find the power rating of your appliance in watts (usually on a label)
- Multiply power (in watts) by hours of use to get watt-hours (Wh)
- Divide by 1,000 to convert to kilowatt-hours (kWh)
- Multiply by your electricity rate to get the cost
Formula: kWh = (Watts × Hours) / 1,000
Energy Saving Tips
Reduce your electricity consumption with these tips:
- Replace incandescent bulbs with LED lights
- Unplug devices when not in use to avoid phantom power draw
- Use energy-efficient appliances (look for Energy Star ratings)
- Adjust thermostat settings for heating and cooling
- Use natural light when possible
- Run dishwashers and washing machines with full loads
- Regular maintenance of HVAC systems
- Install programmable thermostats
Common Appliance Power Ratings
Typical power consumption of household appliances:
| Appliance | Power (Watts) | Typical Usage |
|---|---|---|
| LED Light Bulb | 10-20W | 5-8 hours/day |
| Laptop | 50-100W | 4-8 hours/day |
| Desktop Computer | 200-500W | 8-12 hours/day |
| Refrigerator | 100-800W | 24 hours/day |
| Air Conditioner | 1,000-4,000W | 8-12 hours/day |
| Washing Machine | 500-2,000W | 1-2 hours/day |
| Electric Oven | 2,000-5,000W | 1-2 hours/day |
| TV (LED) | 50-200W | 4-6 hours/day |
Frequently Asked Questions
- How much does 1 kWh of electricity cost?
- The cost of electricity varies by location and provider. In the United States, the average residential rate is around $0.13-$0.15 per kWh, but it can range from $0.10 to $0.30 or more depending on your state and utility company.
- What uses the most electricity in a home?
- Heating and cooling systems typically use the most electricity, accounting for about 40-50% of home energy use. Water heaters, washers/dryers, lighting, and refrigerators are also significant consumers.
- How can I reduce my electricity bill?
- Focus on the biggest energy users: improve insulation, use programmable thermostats, upgrade to energy-efficient appliances, switch to LED lighting, and be mindful of phantom power draw from devices in standby mode.
- What is phantom power or vampire power?
- Phantom power is electricity consumed by devices when they're turned off but still plugged in. This can account for 5-10% of residential electricity use. Unplug devices or use power strips to eliminate phantom power draw.