kWh to Watts Calculator

Q: How do I convert kWh to watts?

To convert kilowatt-hours (kWh) to watts (W), multiply the energy in kWh by 1000, then divide by the time in hours: W = (kWh × 1000) ÷ hours. For example, if a device consumes 2 kWh over 4 hours, its average power draw is (2 × 1000) ÷ 4 = 500 W.

Q: What is the formula for kWh to watts?

The formula is: W = (kWh × 1000) ÷ hours. This works because 1 kilowatt-hour equals 1,000 watt-hours, and power (watts) equals energy (watt-hours) divided by time (hours). Rearranging gives you the average power in watts over the specified time period.

Q: How many watts is 1 kWh?

1 kWh equals different wattages depending on the time period: over 1 hour it equals 1,000 W; over 2 hours it equals 500 W; over 30 minutes (0.5 h) it equals 2,000 W; over 24 hours it equals approximately 41.67 W. kWh is a measure of energy, not power — so the equivalent wattage always depends on time.

Q: What is the difference between kWh and watts?

Watts (W) measure power — the rate at which energy is used at any instant. Kilowatt-hours (kWh) measure energy — the total amount of power consumed over time. A 1,000 W (1 kW) device running for 1 hour consumes 1 kWh. Your electricity bill is measured in kWh because it tracks total energy consumed, not the instantaneous power draw.

Q: My electricity bill shows kWh — how do I figure out which appliance is costing the most?

Use a plug-in energy monitor (e.g., Kill A Watt) to log kWh per appliance, then divide by hours to get average watts. Or check rated wattage and estimate run time: a 1,500 W space heater running 6 h/day uses 9 kWh/day. At $0.15/kWh that is $1.35/day or ~$41/month. Water heaters, AC units, electric dryers, and EV chargers are typically the top four consumers in a US household.

Built by an electrical engineering student Last updated July 2026 Estimates only — how we check

kWh measures energy used over time; watts measures the rate of power. Use this calculator to find the average power draw from any energy reading.

Energy (kWh)

Time (hours)

RESULT — WATTS

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ALSO IN KILOWATTS

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Formula: W = (kWh × 1,000) ÷ hours

How do you convert kWh to watts?

Multiply kWh by 1000, then divide by the number of hours: watts = (kWh × 1000) ÷ hours. If a device uses 2 kWh over 5 hours, its average power is (2 × 1000) ÷ 5 = 400 W. This is the average draw over the period, not the peak.

kWh to Watts Conversion Table

Energy	over 1 h	over 5 h	over 10 h	over 24 h
1 kWh	1000 W	200 W	100 W	41.7 W
2 kWh	2000 W	400 W	200 W	83.3 W
5 kWh	5000 W	1000 W	500 W	208 W
10 kWh	10000 W	2000 W	1000 W	417 W

KWh to Watts Formula

W = (kWh × 1,000) ÷ h

Since 1 kilowatt-hour equals 1,000 watt-hours, multiply your kWh figure by 1,000 to get watt-hours — then divide by the time period in hours to find the average power in watts.

W Power (Watts)

The output — average power draw over the time period

kWh Energy (Kilowatt-hours)

Total energy consumed or generated

h Time (Hours)

The duration over which the energy was used

Quick example: Your fridge logs 3 kWh on your electricity meter over 20 hours. Average power: (3 × 1,000) ÷ 20 = 150 W.

Real-World KWh to Watts Examples

Appliance	Energy Used (kWh)	Time (hours)	Power (Watts)
LED Bulb	0.01 kWh	1 h	10 W
Laptop	0.05 kWh	1 h	50 W
Refrigerator	0.15 kWh	1 h	150 W
Washing Machine	1 kWh	1 h	1,000 W
Air Conditioner	3 kWh	3 h	1,000 W
EV Charger (Level 2)	7.4 kWh	1 h	7,400 W

Understanding Energy vs Power

Watts — Rate of Power

Watts describe how fast energy flows at any given moment. A 100 W bulb always consumes 100 W while switched on — regardless of how long it runs.

W = J ÷ s (joules per second)

kWh — Accumulated Energy

Kilowatt-hours accumulate power over time. That 100 W bulb left on for 10 hours uses 1 kWh — which is exactly what appears on your electricity bill.

kWh = kW × hours

Think of it like driving: your speed (km/h) is like watts — the rate right now. The total distance driven is like kWh — the accumulated result of that speed over time. Knowing only the distance (kWh) and the journey time (hours) lets you calculate the average speed (watts).

Reading Your Electricity Meter: From kWh to Average Watts

Your electricity meter records energy in kWh, not watts. You can use the kWh → watts formula to understand which appliances are responsible for which portion of your bill. The examples below use an illustrative electricity rate of $0.15 per kWh (a common US residential mid-range rate; check your bill for your actual rate):

Electric water heater — 330 kWh / month at $0.15/kWh = $49.50/month.
Average watts = (330 × 1,000) ÷ (30 × 24) = 458 W average. A standard 4,500 W resistive element only runs about 10 % of the time because the tank holds temperature; the average power draw is far lower than the rated wattage on the label.

Central air conditioner — 600 kWh over 30 summer days ($90 at $0.15/kWh).
Average watts = (600 × 1,000) ÷ 720 h = 833 W average over the full month. A 3-ton (10,500 BTU/h) unit draws roughly 3,000–3,500 W when running, meaning the compressor runs approximately 25–28 % of the time on mild summer days — a figure called the duty cycle.

Refrigerator — 45 kWh over 30 days ($6.75/month at $0.15/kWh).
Average watts = (45 × 1,000) ÷ 720 = 62.5 W average. Modern Energy Star refrigerators draw 100–150 W when the compressor is running but cycle on roughly 30–40 % of the time, producing an average around 40–70 W. Older pre-2000 models can run 3× that amount, making refrigerator upgrades one of the highest-ROI household efficiency improvements.

Frequently Asked Questions

How do I convert kWh to watts?

Multiply the energy in kilowatt-hours by 1,000, then divide by the time in hours: W = (kWh × 1,000) ÷ hours. For example, a device consuming 2 kWh over 4 hours has an average power draw of (2 × 1,000) ÷ 4 = 500 W.

What is the formula for kWh to watts?

The formula is: W = (kWh × 1,000) ÷ hours. This works because 1 kilowatt-hour equals 1,000 watt-hours, and power (watts) equals energy (watt-hours) divided by time (hours). The result is the average power over the specified period — not an instantaneous reading.

How many watts is 1 kWh?

1 kWh converts to different wattages depending on the time period:

Over 1 hour: (1 × 1,000) ÷ 1 = 1,000 W
Over 2 hours: (1 × 1,000) ÷ 2 = 500 W
Over 30 minutes (0.5 h): (1 × 1,000) ÷ 0.5 = 2,000 W
Over 24 hours: (1 × 1,000) ÷ 24 ≈ 41.67 W

kWh is a measure of energy, not power — so the watt equivalent always depends on time.

What is the difference between kWh and watts?

Watts (W) measure power — the rate at which energy is used at any instant. Kilowatt-hours (kWh) measure energy — the total power consumed over time. A 1,000 W (1 kW) device running for 1 hour consumes 1 kWh. Your electricity bill is measured in kWh because it tracks total energy consumed, not instantaneous power. The relationship is: kWh = kW × hours.

My electricity bill shows kWh — how do I figure out which appliance is costing the most?

Use a plug-in energy monitor (e.g., Kill A Watt) or a smart meter to log kWh per appliance over a day or week, then divide by hours to get average watts. Alternatively, check the appliance's rated wattage and estimate running time: a 1,500 W space heater running 6 hours/day uses 9 kWh/day. At $0.15/kWh that is $1.35/day or about $41/month. Water heaters, air conditioners, electric dryers, and EV chargers are almost always the top four consumers in a typical US household.