Electrical Calculator
Electricity Cost Calculator
Estimate electricity cost per day, month, or year using watts, hours used, number of days, and rate per kWh.
What this calculator does
This calculator provides a simple electricity cost estimate using device power, daily operating time, number of days, and a flat electricity rate per kWh.
It is useful for quick estimates involving appliances, heaters, office equipment, small machines, lighting loads, or rough monthly energy cost checks.
Inputs
Result
How to read the result
The energy result shows how much electricity the load is expected to use over the selected period. The cost result is a simple estimate based on the rate you entered.
This is most useful for rough comparison, budgeting, and quick usage checks. The daily, monthly, and yearly estimates help you see the cost impact at different time scales, but they should not be treated as an exact utility bill prediction.
Formula
Energy (Wh) = Power (W) × Hours per Day × Days
Energy (kWh) = Energy (Wh) ÷ 1000
Cost = Energy (kWh) × Rate per kWh
Worked example
If a device uses 500W for 5 hours a day over 30 days:
500 × 5 × 30 = 75,000 Wh
75,000 Wh ÷ 1000 = 75 kWh
If the rate is 140 per kWh, then cost = 75 × 140 = 10,500
Common electricity cost examples
How much does 250W cost per hour?
A 250W device uses 0.25 kWh per hour. At 0.15 per kWh, it costs about 0.0375 per hour.
How much does 600W cost per hour?
A 600W device uses 0.6 kWh per hour. At 0.15 per kWh, it costs about 0.09 per hour.
How much does 100W cost to run?
A 100W device running 10 hours a day uses 1 kWh per day. Multiply that by your rate per kWh to estimate daily cost.
How much does 500W cost per month?
A 500W device running 5 hours a day for 30 days uses 75 kWh in a month. Multiply 75 by your rate per kWh for a monthly estimate.
How much does 1000W cost to run?
A 1000W load uses 1 kWh per hour. If your rate is 0.15 per kWh, that is about 0.15 per hour of use.
How much does a 1500W heater cost to run?
A 1500W heater uses 1.5 kWh per hour. Multiply 1.5 by your electricity rate to estimate hourly cost.
How much does a 2000W appliance cost per hour?
A 2000W load uses 2 kWh per hour. Multiply 2 by your rate per kWh for a quick hourly estimate.
How do I estimate yearly electricity cost?
First estimate daily energy use in kWh, multiply by your rate, then multiply by 365 for a rough yearly cost.
Quick kWh cost reference
75 kWh cost
At 0.15 per kWh, 75 kWh costs 11.25. At 0.20 per kWh, 75 kWh costs 15.00.
365 kWh cost
At 0.15 per kWh, 365 kWh costs 54.75. At 0.20 per kWh, 365 kWh costs 73.00.
500 kWh cost
At 0.15 per kWh, 500 kWh costs 75.00. At 0.20 per kWh, 500 kWh costs 100.00.
Cost to run common household and work loads
Lighting and small electronics
Small loads such as LED lighting, monitors, and networking devices usually consume less power, but their long operating hours can still add up.
Heaters and high-power appliances
Space heaters, kettles, cookers, and other high-wattage devices can change daily and monthly electricity cost much more quickly.
Office and workshop equipment
Printers, compressors, tools, and office devices often have intermittent use, so comparing cost by hour and by month is especially helpful.
Important notes
This is a flat-rate estimate
Many real electricity billing systems use tiered pricing, taxes, demand charges, or fixed fees. This page does not include those details.
Actual usage may vary
Some devices do not run at their rated power continuously. Real energy consumption may be lower or higher depending on operating conditions.
This is a quick reference tool
Use this calculator for simple comparison and estimation, not final utility billing verification.
FAQ
Does this include tiered electricity billing?
No. This is a simple estimate using a flat rate per kWh.
What unit should I enter for the rate?
Enter the cost for 1 kWh in your local currency or billing unit.
Can I use this as an electricity bill calculator?
Yes, for a rough bill estimate. It works best when your billing plan uses a simple flat kWh rate.
Can I use this for monthly estimates?
Yes. The default value is 30 days to make monthly estimation easier.
Can I estimate daily and yearly electricity cost too?
Yes. This page shows daily and yearly cost estimates so you can compare short and long-term usage impact.
How much does 75 kWh cost?
Multiply 75 by your electricity rate per kWh. For example, at 0.15 per kWh, 75 kWh would cost 11.25.
Why can the real bill differ from this result?
Real utility billing may include tiered pricing, service fees, taxes, and differences between rated and actual equipment consumption.