Electricity Calculator - Free Online Calculator
Find out what an appliance costs to run. Enter its power rating, how long you use it and your electricity price.
- Formula shown on the page
- Runs in your browser
- Your inputs stay private
Energy per month
135 kWh
Cost per month
₹1,080.00
Cost per year
₹12,960
Energy per day
4.5 kWh
Current drawn
6.52 A
Understanding the Electricity Calculator
Some tasks are specific enough that you'd normally reach for a separate app or browser extension - but really only come up once in a while. The Electricity Calculator is the browser-based version: free, no account needed, works on any device, and the result is there in a few seconds. Nothing you enter is sent anywhere; everything happens on your device.
If the Electricity Calculator is something you use regularly, bookmark it. Most of our utilities continue working offline once the page has loaded, which is handy when you're on a slow connection or need to get something done quickly without waiting for a server. The URL stays stable, so you can share it with anyone who needs the same tool.
Using the Electricity Calculator in 3 steps
Enter the appliance wattage from its label.
Enter hours of use per day and days per month.
Enter your price per kWh and read the cost.
How the Electricity Calculator works
Energy in kilowatt-hours is power in kilowatts multiplied by hours. Cost is energy times the unit price.
kWh = watts x hours / 1000 | cost = kWh x price
- wattspower rating
- kWhkilowatt-hours
How the Electricity Calculator gets its answer
The Electricity Calculator runs entirely in your browser. There's no upload, no remote server, no analytics on your inputs. For utilities that need fresh data (timezones, weather, currency rates), the calculator fetches from a public API - but only the bare query is sent, nothing about who you are.
Privacy and speed are the two design goals. The Electricity Calculator is statically rendered so the page loads in under a second on most connections, and the actual computation happens on your device - typically in milliseconds. There's no spinner, no "calculating...", no waiting on someone else's server.
When to use the Electricity Calculator
- One-off needs that don't justify installing an app or signing up for a service.
- Privacy-sensitive computations where you'd rather not send data to a third-party server.
- Quick checks on a phone or shared computer where installing software isn't an option.
- Teaching or demonstrating - the URL works the same on every device and platform.
Common mistakes and gotchas
- Assuming a utility tool replaces a security audit. Password generators are good defaults, but truly sensitive accounts need a dedicated password manager.
- Treating output of a generator as a guarantee. Random number generators, dice rollers and similar tools use cryptographically-strong randomness, but you should still verify behaviour for any high-stakes use case.
- Forgetting that browser-side tools are subject to the device they run on. A compromised browser can leak inputs even if the tool itself doesn't transmit them.
- Not bookmarking the page if you'll use the Electricity Calculator regularly - the URL is the cheapest way to find it again.
Get more out of this tool
- Bookmark the Electricity Calculator page if you use it more than once a week.
- Pair the Electricity Calculator with other utilities on this site - many are designed to work together (e.g., date difference + age calculator, password generator + secure storage tools).
- Most utilities work offline after first load. Useful when you're on a flight or in patchy network conditions.
- Share the URL with anyone who needs the same tool - no install, no signup, just a link.
Questions about the Electricity Calculator
What is a kWh?
The energy used by a 1000 watt appliance running for one hour.
Where do I find the wattage?
On the appliance's rating label or manual.
Small tools that save real time
Date math, password generation, QR codes, IP subnets, base64 encoding, dew point, dice rolls, age calculations - none of these are 'big' problems individually, but they are the small frictions that interrupt your day. This tool runs entirely in your browser, has no popup, no chat widget and no tracking inside the calculation, so you can finish the task and move on.
Many tools in the Daily Utilities category complement each other - date difference + day counter + day-of-the-week, or password generator + QR code + base64 encoder. The related-tool grid links them together so you can move between adjacent problems in a click.
The Electricity Calculator is part of the Daily Utilities suite on Online Calculator Tools, alongside 5 related calculators. All tools share the same UI patterns, the same privacy-first rendering (nothing is sent to a server), and the same commitment to showing the formula and assumptions behind every result.