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Practical electricity calculator
Estimate how much an appliance costs to run for one hour. This is a fast way to compare devices, check whether a heater or fan is low-cost to run for a short time, or understand the hourly cost of several identical appliances.
One-hour running-cost check
This tool focuses on short time windows, so you can see the cost of one hour first and then use that same estimate to think about longer sessions.
How to read the result
The hourly result is most useful for short-session decisions. It helps you compare active-use habits, check the cost of a brief session, or decide whether leaving a device on for a few hours is likely to matter.
A very small hourly cost can still add up when a device runs every day or stays on for 24 hours. A larger hourly cost may be less important if the appliance is only used occasionally. For regular use, look at the 8-hour and 24-hour results as reference points for a possible monthly habit.
If you are comparing two appliances, focus on the difference between their hourly costs rather than the number in isolation. If the difference is tiny, comfort, noise, or performance may matter more. If the difference is large and the appliance runs often, it may be worth measuring the actual setup more carefully.
For longer recurring use, move to the Appliance Electricity Cost Calculator. If you first need to convert wattage and time into kWh, use the Watts to kWh Calculator. To choose between the full set of electricity tools and guides, visit the Electricity Cost Calculators hub. If you want to understand why the calculator uses kWh even for a one-hour estimate, see Watts vs kWh explained.
Decision point
A one-hour estimate is useful for short comparisons. If the same appliance runs every day, the next useful question is usually daily or monthly usage cost, not another hourly example.
If you already know the appliance runs as a daily habit, use the Appliance Electricity Cost Calculator so the estimate can show daily, monthly, and yearly usage cost.
Example
An hourly calculator is useful when appliances are used for different reasons but compete for the same household budget. A small fan may have a very low hourly cost, a desktop PC may sit in the middle, and a portable heater may cost much more per hour because of its higher wattage.
The hourly number helps with one-hour comparisons, but the 8-hour result is often more realistic for workdays, gaming sessions, overnight fan use, or heating one room in the evening. If a device is used that often, move to the daily and monthly calculator to understand the longer-term impact.
| Device | Watts | Cost per hour at 0.20/kWh |
|---|---|---|
| Fan | 75 W | 0.02 |
| Gaming PC | 400 W | 0.08 |
| Space heater | 1500 W | 0.30 |
Calculation logic
The tool converts total appliance wattage into kWh for one hour, then multiplies that by the electricity rate you entered. It also multiplies the hourly cost by 8 and 24 to show two longer reference points.
Formula: hourly cost = (watts x quantity / 1000) x electricity rate
Common uses
FAQ
Many appliances use only a fraction of one kWh in a single hour, so the cost for that hour can be a small decimal amount even when the monthly total becomes noticeable over time.
Yes. Increase the quantity field if several identical appliances are operating together.
No. This is a usage-based estimate only. Real bills can also include delivery fees, taxes, tiered rates, and fixed charges. If you want the common reasons behind a bigger real bill, read why your electric bill is higher than the calculator estimate.
Use the related appliance electricity cost calculator if you want daily, monthly, and yearly estimates based on hours used per day.
The estimate is based on the wattage you enter, so it usually represents active running power. Standby power is often lower and should be estimated separately if you want to understand plugged-in idle cost.
Hourly cost is better for a quick side-by-side comparison. Daily, monthly, or yearly cost is better when the same appliance becomes a regular habit.
Yes. Run the calculator once for each appliance using the same electricity rate. The difference between the hourly results shows which one is cheaper to operate for the same amount of time.
Electricity cost often grows through repetition. A few cents per hour may not seem important, but the total changes when the appliance runs for many hours every day.
Related tools
Choose the next calculator from the number you have now: watts, kWh, a one-hour check, or a full appliance-use estimate.
Home energy
What it shows
Estimate the daily, monthly, and yearly electricity cost of an appliance from its wattage, usage hours, and electricity rate.
Best for
Comparing the running cost of heaters, fans, computers, kitchen appliances, and other devices before you buy or leave them on every day.
Home energy
What it shows
Convert appliance wattage and runtime into kWh so you can estimate energy use before working out electricity cost.
Best for
Turning an appliance label in watts into usable energy consumption over a chosen number of hours.
Home energy
What it shows
Convert a known kWh amount into estimated electricity cost using your rate per kWh.
Best for
Turning known energy use from a bill, meter, appliance estimate, or watts-to-kWh result into a practical cost estimate.
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