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kW to kWh Calculator

Convert power (kilowatts) to energy (kilowatt-hours) for any time period.

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1kWh
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Understanding kW and kWh

To effectively use this calculator, it's important to understand the difference between kilowatts (kW) and kilowatt-hours (kWh):

Kilowatt (kW)

A kilowatt is a unit of power (the rate at which energy is generated or consumed).

Think of kilowatts as speed or rate — how quickly energy is being used at a specific moment.

Example: An air conditioner that draws 2.5 kW of electricity when running.

Kilowatt-hour (kWh)

A kilowatt-hour is a unit of energy (the total amount of electricity used over time).

Think of kilowatt-hours as distance or volume — the total accumulated energy consumed.

Example: The same air conditioner running for 2 hours consumes 5 kWh of energy (2.5 kW × 2 hours).

How to Convert kW to kWh

The conversion from kilowatts to kilowatt-hours is straightforward:

kWh = kW × time (in hours)

If your time is not in hours, you'll need to convert it first:

  • Minutes to hours: divide by 60 (e.g., 30 minutes = 0.5 hours)
  • Days to hours: multiply by 24 (e.g., 2 days = 48 hours)
  • Weeks to hours: multiply by 168 (e.g., 1 week = 168 hours)
  • Months to hours: multiply by approximately 730 (e.g., 1 month ≈ 730 hours)

Example Calculations

Example 1: Home Appliance

A 1.5 kW heater runs for 3 hours:
Energy = 1.5 kW × 3 hours = 4.5 kWh

Example 2: Industrial Equipment

A 75 kW motor runs for 8 hours a day for 22 working days:
Daily energy = 75 kW × 8 hours = 600 kWh
Monthly energy = 600 kWh × 22 days = 13,200 kWh

Example 3: Short Duration

A 2 kW microwave runs for 5 minutes:
Time in hours = 5 ÷ 60 = 0.0833 hours
Energy = 2 kW × 0.0833 hours = 0.1667 kWh

Common Household Appliance Power Ratings

Here are typical power ratings for common household appliances:

ApplianceTypical Power (kW)Energy Used in 1 Hour (kWh)
LED Light Bulb0.010.01
Ceiling Fan0.060.06
Laptop Computer0.05-0.10.05-0.1
Television (LED, 50")0.08-0.120.08-0.12
Refrigerator0.1-0.40.1-0.4
Washing Machine0.4-0.70.4-0.7
Dishwasher1.2-1.51.2-1.5
Microwave Oven0.6-1.50.6-1.5
Electric Oven2.0-2.52.0-2.5
Air Conditioner (Window)0.7-1.50.7-1.5
Air Conditioner (Central)3.0-5.03.0-5.0
Electric Water Heater3.0-4.53.0-4.5
Electric Clothes Dryer3.0-5.03.0-5.0
Electric Car Charger (Level 2)3.3-19.23.3-19.2

Note: Actual power consumption may vary based on the specific model, usage patterns, and efficiency rating.

Practical Applications

Understanding the kW to kWh conversion is useful for:

  • Estimating energy bills: Calculate how much electricity appliances use over time
  • Energy efficiency planning: Compare energy consumption of different devices
  • Solar panel sizing: Determine how much energy your solar panels will generate
  • Battery capacity calculations: Figure out how long batteries will last
  • Industrial planning: Estimate energy requirements for factories and facilities
  • EV charging: Calculate charging times and costs for electric vehicles

Tips for Reducing Energy Consumption

Now that you understand kW and kWh, here are some ways to reduce your energy usage:

  1. Replace high-wattage appliances with energy-efficient models (look for ENERGY STAR ratings)
  2. Use appliances with lower power ratings where possible
  3. Reduce the time appliances are in use, especially high-power ones
  4. Install smart plugs or energy monitors to track consumption
  5. Use timers for devices that don't need to run continuously
  6. Consider using solar power for some of your energy needs

Understanding Your Electricity Bill

Electricity providers charge based on the total energy consumed (kWh), not on the power rating (kW) of your devices. The average cost per kWh in the United States ranges from about $0.10 to $0.30, depending on your location.

For a quick estimate of an appliance's operating cost:

Cost = Energy (kWh) × Rate ($/kWh)

Example: If electricity costs $0.15 per kWh and an air conditioner uses 3 kWh per hour, running it for 5 hours costs:
3 kWh × 5 hours × $0.15/kWh = 15 kWh × $0.15/kWh = $2.25

Other Common Energy Unit Conversions

  • 1 kWh = 3.6 megajoules (MJ)
  • 1 kWh = 3,412 British Thermal Units (BTU)
  • 1 kWh = 860 kilocalories (kcal)
  • 1 megawatt-hour (MWh) = 1,000 kWh
  • 1 gigawatt-hour (GWh) = 1,000,000 kWh

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