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Convert Watts to kWh Instantly

Free energy & cost calculator — enter any appliance's wattage and see your exact electricity cost in seconds.

State rates referenced — JANUARY 2026
7 days
$
Energy Consumed (Per Usage)
0.00 kWh
Est. Cost: $0.00
Monthly Projection 0.0 kWh
$0.00
Yearly Outlook 0.0 kWh
$0.00

Rates based on EIA 2026 US Average data.

Quick Links & Navigation

  1. 1 Watts vs kWh Difference →
  2. 2 Conversion Formula →
  3. 3 kW vs kWh Explanation →
  4. 4 Appliance Usage Guide →
  5. 5 Regional Electricity Rates →
  6. 6 Watts, Amps, & Volts →
  7. 7 FAQ (15 Most-Asked) →

1. What Is the Difference Between Watts and kWh?

Watts measure power — the rate at which energy is used at any given moment. Kilowatt-hours measure energy — the total amount of electricity consumed over time. Think of watts like speed and kWh like distance. You need both to understand your electricity bill.

Term Measures Symbol Real-World Example
Watt (W) Power (rate) W A 60W LED bulb
Kilowatt (kW) 1,000 watts of power kW A 3kW electric oven
Kilowatt-Hour (kWh) Energy used over time kWh 1 kW running 1 hour = 1 kWh

2. The Watts to kWh Formula (With Examples)

Converting watts to kWh is a simple two-step process.

$$kWh = \frac{Watts \times Hours}{1,000}$$

🔥 Space Heater Example

Inputs: 1,500W heater, 8 hours/day.

Calculation: (1,500W × 8 hours) / 1,000 = 12 kWh.

💡 LED Bulb Example

Inputs: 10W bulb, 4 hours/day.

Calculation: (10W × 4 hours) / 1,000 = 0.04 kWh.

4. Real Appliance Wattage Guide

Understanding exactly how many watts your appliances use is the first step toward reducing your bill. This guide covers common household electronics and their power draw.

Appliance Typical Wattage Usage Pattern Est. Daily Cost (Avg)
Coffee Maker 800W - 1,200W 15 mins $0.04 - $0.06
Central Air Conditioning 3,000W - 5,000W 6 - 12 hours $3.24 - $10.80
Gaming PC 300W - 600W 4 - 8 hours $0.22 - $0.86
Refrigerator 100W - 250W 8 hours (Cycle) $0.14 - $0.36
LED Light Bulb 6W - 12W 5 hours $0.01

14. Frequently Asked Questions

How many kWh does the average US home use per month?
The average US household uses about 886 kWh per month (about 29 kWh per day), according to the US Energy Information Administration. This varies significantly by state — Louisiana averages 1,291 kWh/month while Hawaii averages just 506 kWh/month.
How do I convert kWh back to watts?
Divide kWh by the number of hours to get kW, then multiply by 1,000. Watts = (kWh ÷ Hours) × 1,000 Example: 6 kWh used over 4 hours = 1.5 kW = 1,500 watts
Is kWh the same as kilowatts?
No. Kilowatts (kW) measure power (rate). Kilowatt-hours (kWh) measure energy (total). Your utility bills you for kWh, not kW. A 2kW device running for 3 hours uses 6 kWh.
What is 1 kWh in simple terms?
1 kWh is the energy used by a 1,000-watt device running for exactly 1 hour. Examples: a hair dryer (1,000W) for 1 hour, or a 100W bulb for 10 hours. Both equal 1 kWh.
How much does it cost to run a 1,500W heater for 8 hours?
1,500 ÷ 1,000 = 1.5 kW. 1.5 × 8 hours = 12 kWh. At $0.13/kWh = $1.56. At California’s $0.22/kWh = $2.64.
What uses the most electricity in a home?
HVAC (heating and cooling) accounts for 45–50% of most home electricity bills. Water heating is next at 14–18%. After that: washer/dryer (5–6%), refrigerator (4–6%), and lighting (4–5%).
How many watts does a house use?
The average US home uses about 1,228 watts continuously (886 kWh/month ÷ 720 hours). Peak usage during evening hours is typically 3,000–6,000 watts.
What is the difference between Wh and kWh?
Watt-hours (Wh) and kilowatt-hours (kWh) measure the same thing — energy. 1 kWh = 1,000 Wh. Wh is used for smaller devices (batteries, laptops). kWh is used for home appliances and utility billing.
How do I find the wattage of a device?
Check the label on the device itself (usually on the bottom or back), or look it up in the manual or manufacturer’s website. The label will show watts (W) or amps (A) and volts (V). If it shows amps and volts, multiply them to get watts.
How many kWh does a solar panel produce per day?
A typical 400W solar panel produces 1.2–2.0 kWh per day, depending on location and sun hours. In a sunny region like Arizona (6 peak sun hours): 400W × 6 hrs = 2.4 kWh per day.
What is a BTU and how does it relate to kWh?
BTU (British Thermal Unit) is a unit of thermal (heat) energy. 1 kWh = 3,412 BTU. AC units are rated in BTU per hour to indicate cooling power. A 12,000 BTU/hr AC = 3.5 kWh per hour of operation.
How many kWh does it take to charge an electric car?
It depends on the battery size. A Tesla Model 3 Standard Range (57.5 kWh) needs 57.5 kWh to go from empty to full. In practice, most EV owners top up daily, adding 10–20 kWh per session. At $0.13/kWh, a full charge costs $7.50–17.00.
What is a kVA and how is it different from kW?
kVA (kilovolt-ampere) is apparent power. kW is real power. The relationship is: kW = kVA × Power Factor. For purely resistive loads (heaters, incandescent bulbs), power factor = 1, so kVA = kW. For motors and electronics, power factor is typically 0.8–0.95.
How many watts is a typical house circuit?
A standard 15-amp, 120V circuit handles up to 1,800W (15A × 120V). A 20-amp circuit handles up to 2,400W. Kitchen and bathroom circuits are usually 20A. Dryers and EV chargers use 240V circuits at 30–50 amps.
How do I reduce my kWh usage this month?
The fastest wins: switch to LED bulbs, unplug standby devices, adjust your thermostat by 2–3 degrees, and shift laundry and dishwasher use to off-peak hours. Together these can cut 50–150 kWh per month with zero comfort sacrifice.

Our Mission

At WattsToKwh.com, we simplify complex energy calculations for homeowners. Our goal is to help you understand your energy footprint so you can save money, reduce waste, and build a more sustainable home. Every calculation is verified against IEEE standards and US government energy data.