kWh Cost Calculator

Enter a device's watts and hours, a number of kWh, or a bill, with your own price per kWh, to see the cost.

Embed

Embed this tool

Copy this code into your website, blog or class page. The tool runs inside your page.

1. Embed code

<iframe src="https://chargevolthub.com/kwh-cost-calculator/?embed=1&ref=embed" width="100%" height="640" style="border:0;max-width:100%" title="kWh Cost Calculator" loading="lazy" allow="fullscreen; autoplay"></iframe>
<p>Tool by <a href="https://chargevolthub.com/kwh-cost-calculator/" rel="nofollow">kWh Cost Calculator – ChargeVoltHub</a></p>

2. Optional: resize the frame to fit the tool (add once per page)

<script>addEventListener('message',function(e){if(e.origin!=='https://chargevolthub.com')return;var h=e.data&&e.data.tkEmbedHeight;if(!h)return;document.querySelectorAll('iframe').forEach(function(f){if(f.contentWindow===e.source)f.style.height=h+'px'})})</script>

Please keep the credit link below the tool.

This kWh cost calculator does three jobs with your own electricity price. It works out what a device costs to run from its watts and hours of use, what a number of kWh costs, and, as a cost per kWh calculator, the price per kWh hidden in a bill. Results are shown per day, per week, per month and per year, with every step written out. The page holds no price list: you enter the rate from your bill or tariff, so the answer is yours rather than an average. It is free, runs in your browser, needs no sign-up and uploads nothing.

How to use the kWh cost calculator

Under Work out, choose Cost of running a device, Cost of a number of kWh or Price per kWh from a bill.
For a device, enter the Device power (the wattage on its label, in W or kW) and the Hours of use per day.
For a number of kWh, enter the Energy used (kWh) from your meter or bill.
Enter your Price per kWh from your bill or tariff. The 0.18 shown is only an example, not a typical price.
For a bill, enter the Bill total and the kWh on the bill for the same period. If the bill has standing or connection charges, enter them under Fixed charges to also see the energy-only rate.
Open More options to set the Days of use per week (7 means every day) and a Currency symbol.

Read the result rows, then open the steps to see the calculation with your numbers. The table under a device result shows the same device for 1 to 24 hours a day. Example buttons above the form load a 1,500 W device used 4 hours a day, a 100 W device left on all day, 350 kWh in a month, and a bill with fixed charges. Copy link keeps all inputs in the page address, and Print / save as PDF saves a dated copy.

How do you calculate the cost of kWh?

Multiply the kWh by the price per kWh. A device uses its power in kilowatts multiplied by the hours it runs, so kWh = watts ÷ 1,000 × hours. The U.S. Energy Information Administration shows the idea with a 40 W bulb used for five hours: 200 Wh, or 0.2 kWh.

For example, a 1,500 W device used 4 hours a day uses 1.5 kW × 4 h = 6 kWh a day. At 0.18 per kWh that costs 6 × 0.18 = 1.08 a day. Over a year of daily use that is 6 × 365 = 2,190 kWh, or 394.20, and a month is a twelfth of the year, 182.5 kWh or 32.85.

How much does it cost to leave a device on all day?

Use the device’s watts, 24 hours a day. A 100 W device left on all day uses 100 ÷ 1,000 × 24 = 2.4 kWh a day. At 0.20 per kWh that is 0.48 a day, and over 365 days it is 876 kWh, or 175.20. Switch the days per week lower if it only runs on some days.

How do you work out the cost per kWh from a bill?

Divide the bill total by the kWh used in the same period. This is a simple cost per kWh calculator: a 120 bill for 800 kWh is 120 ÷ 800 = 0.15 per kWh.

That figure includes everything on the bill. If part of it is a fixed charge that does not change with use, take it off first to get the energy-only price. With 20 of fixed charges, (120 − 20) ÷ 800 = 0.125 per kWh. Which charges count as fixed depends on your tariff, so read your bill. For a public EV charging bill with per-minute and session fees, use the EV charging cost per kWh calculator.

How do I find the watts of a device?

Look for the wattage on the label or in the manual. If only volts and amps are given, watts are volts × amps for a simple resistive load. If you have a label in kW, choose kW in the unit box. A device that cycles on and off, such as a fridge, draws its label power only part of the time, so use the hours it is actually drawing power.

Worked examples

Input	Result
1500 W for 4 h a day, 7 days a week, $0.18 per kWh	6 kWh a day, $1.08 a day, $394.20 a year
100 W for 24 h a day, 5 days a week, $0.20 per kWh	2.4 kWh a day, $0.48 a day, $125.14 a year
350 kWh at $0.18 per kWh	$63.00
$120.00 bill for 800 kWh, $20.00 fixed charges	$0.1500 per kWh including everything; $0.1250 per kWh for energy only

Calculated by the tool above with these values.

Frequently asked questions

What price per kWh should I enter?

Use the rate on your own bill or tariff. The calculator has no built-in prices, and the 0.18 shown is only an example. If your tariff changes by time of day, enter the rate that applies when the device runs.

How are the monthly and yearly costs worked out?

The yearly figure is the energy per day of use × days of use per week × 365 ÷ 7, times your price. A month is one twelfth of a year, so every month has the same figure.

Does the price per kWh from a bill include taxes and fees?

It includes whatever is in the bill total you enter, so a total with taxes and fees gives an all-in price per kWh. Use the fixed charges box to remove standing charges and see the energy-only price.

Can I use it for an EV charging session?

Yes, for home charging: enter the kWh added to the battery and your rate. The kWh drawn from the wall is slightly higher than the kWh added to the battery, so for a full estimate with charging loss use the EV charging cost calculator on the home page.

Does the calculator save what I enter?

No. Everything runs in your browser and nothing is uploaded. The inputs only appear in the page address if you copy the link.

kWh to watts converter — Use it to convert kWh to watts, or watts to kWh, over a length of time.
EV charging cost calculator — Use it to estimate what an EV charge costs from your electricity price.
EV charging cost per kWh calculator — Use it to find the real price per kWh of a public charging bill.
EV cost per mile calculator — Use it to turn a kWh price into a cost per mile.
All EV calculators — Use it to browse every calculator on the site.

Sources

U.S. Energy Information Administration, Measuring electricity: kilowatt-hour definition and the 40 W bulb example