kW to kWh Calculator

Convert kilowatts (kW) to kilowatt‑hours (kWh), estimate energy use for one or more appliances, and see your electricity cost.

Quick kW to kWh Conversion

kW
hours

Appliance Energy & Cost Estimator

Add one or more appliances, choose power in watts or kilowatts, set how long they run, and optionally include duty cycle (how often they are actually on).

Appliance Power Hours / day Days Duty cycle (%) Energy (kWh)
$ per kWh

Use your local rate from your bill (or any currency symbol).

0 kWh
0.00

How to convert kW to kWh

Kilowatts (kW) measure power – how fast energy is used or produced. Kilowatt‑hours (kWh) measure energy – how much is used over time.

Basic formula

\( \text{kWh} = \text{kW} \times \text{hours} \)

Steps:

  1. Find the power rating of the device in kW (or convert watts to kW by dividing by 1000).
  2. Estimate how many hours it runs.
  3. Multiply: kWh = kW × hours.

Example 1 – Single appliance

A 1.2 kW space heater runs for 5 hours:

\( \text{kWh} = 1.2\ \text{kW} \times 5\ \text{h} = 6\ \text{kWh} \)

Example 2 – Power in watts

A 1500 W heater runs for 3 hours. First convert watts to kilowatts:

\( \text{kW} = \dfrac{\text{W}}{1000} = \dfrac{1500}{1000} = 1.5\ \text{kW} \)

\( \text{kWh} = 1.5\ \text{kW} \times 3\ \text{h} = 4.5\ \text{kWh} \)

Including duty cycle (on/off cycling)

Many devices (like fridges or air conditioners) are not on 100% of the time. If a 1 kW AC runs 8 hours per day but the compressor is on only 40% of the time:

\( \text{Effective hours} = 8 \times 0.40 = 3.2\ \text{h} \)

\( \text{kWh} = 1\ \text{kW} \times 3.2\ \text{h} = 3.2\ \text{kWh} \)

The multi‑appliance calculator above lets you enter duty cycle directly.

kW vs kWh: what’s the difference?

  • kW (kilowatt) – instantaneous power. Think of it like the speed of a car (km/h or mph).
  • kWh (kilowatt‑hour) – accumulated energy. Think of it like the total distance driven.

Your electricity meter and bill are based on kWh, not kW. The higher the kW and the longer it runs, the more kWh you use.

Estimating your electricity bill from kWh

Once you know your total kWh, estimating cost is straightforward:

Cost formula

\( \text{Cost} = \text{kWh} \times \text{rate per kWh} \)

If you use 250 kWh in a month and your rate is $0.20 per kWh:

\( \text{Cost} = 250 \times 0.20 = \$50 \)

In the calculator, enter your rate (for example 0.20) and it will compute the total cost automatically.

Typical appliance power ratings

Approximate power ratings to help you estimate usage:

  • LED bulb: 5–15 W (0.005–0.015 kW)
  • Refrigerator: 100–300 W average (0.1–0.3 kW)
  • Window AC: 500–1500 W (0.5–1.5 kW)
  • Electric kettle: 1500–2200 W (1.5–2.2 kW)
  • Electric oven: 2000–4000 W (2–4 kW)
  • Clothes dryer: 2000–5000 W (2–5 kW)

Use these values as a starting point if you can’t find the exact rating label on your device.

FAQ

How do you convert kW to kWh?

Multiply the power in kW by the time in hours: kWh = kW × hours. The quick converter at the top does this instantly for you.

How many kWh is 1 kW for 24 hours?

1 kW × 24 hours = 24 kWh. This is a common way to estimate daily energy use of a device that runs continuously.

Can I convert kWh back to kW?

Yes, if you know the time period. Rearrange the formula:

\( \text{kW} = \dfrac{\text{kWh}}{\text{hours}} \)

For example, 12 kWh used over 4 hours corresponds to an average power of 12 ÷ 4 = 3 kW.

Does voltage or current matter for kW to kWh?

Not directly. kW already includes voltage and current (kW ≈ V × A × power factor ÷ 1000). Once you know kW, converting to kWh only depends on time.