kWh Cost Calculator
Estimate the electricity use and running cost of any appliance using watts, hours, and your electricity rate.
What is kWh cost?
kWh cost is the amount of money you pay for every kilowatt-hour of electricity you use. A kilowatt-hour is a unit of energy: using a 1,000-watt appliance for one hour equals 1 kWh. Utility companies charge your bill based on total monthly kWh consumption multiplied by your rate.
If you know your power usage and your electricity rate, you can estimate costs for any device: air conditioner, heater, gaming PC, refrigerator, EV charger, lights, or even a coffee machine. That is exactly what this calculator does.
How to calculate electricity cost from watts
Core formula
Energy (kWh) = (Watts × Hours of use × Quantity) ÷ 1000
Cost = Energy (kWh) × Electricity rate ($/kWh)
For monthly and yearly estimates, multiply daily energy by the number of days used per month, then by 12 for annual totals. If your bill includes taxes or delivery charges as a percentage, add that amount after calculating base cost.
Quick reference examples
| Appliance | Typical Watts | Daily Use | Daily kWh |
|---|---|---|---|
| LED TV | 100 W | 5 hrs | 0.50 kWh |
| Space Heater | 1500 W | 4 hrs | 6.00 kWh |
| Laptop | 60 W | 8 hrs | 0.48 kWh |
| Window AC | 1200 W | 6 hrs | 7.20 kWh |
How to use this calculator kWh cost tool
- Enter the appliance power in watts.
- Enter how many hours it runs each day.
- Set days used per month (usually 30).
- Add your utility rate in $/kWh from your electric bill.
- Adjust quantity if you have multiple units.
- Optionally add standby watts and standby hours.
- Click Calculate Cost to see daily, monthly, and yearly impact.
Why this matters for your budget
Small usage decisions can create large annual differences. A high-watt appliance used for a few hours each day may add hundreds of dollars per year. Likewise, always-on standby devices can quietly increase your baseline consumption. Tracking kWh cost helps you prioritize upgrades and habits that actually reduce your electric bill.
High-impact ways to reduce electricity costs
- Replace old resistance heaters or inefficient AC units with higher-efficiency models.
- Use programmable thermostats and smart schedules.
- Run dishwashers and laundry with full loads and lower temperature settings when possible.
- Seal leaks and improve insulation to reduce heating/cooling runtime.
- Switch to LED lighting and turn off unnecessary loads.
- Use smart power strips to cut standby power draw.
FAQ
Is kW the same as kWh?
No. kW measures power (rate of use), while kWh measures energy used over time. Bills are based on kWh, not just kW.
Where do I find my electricity rate?
Check your utility bill under “price per kWh,” “energy charge,” or “supply charge.” Some plans have tiered or time-of-use rates, so your true average may vary.
Can this estimate full household cost?
Yes, by calculating major appliances one-by-one and summing results. For the best estimate, include HVAC, water heating, refrigeration, laundry, cooking, electronics, and lighting.
Final takeaway
A simple kWh cost calculation gives you control over your energy spending. Use the calculator above to test scenarios, compare appliances, and identify the biggest opportunities to cut monthly utility bills without sacrificing comfort.