Appliance annual energy costs
List appliance wattage, hours/day, days/year and your kWh price. Annual energy and costs are estimates, not measurements.
- Runs in your browser
- No upload
- Check before download
List appliance wattage, hours/day, days/year and your kWh price. Annual energy and costs are estimates, not measurements.
Calculations run locally and inputs are not saved automatically. Download an input backup before closing the tab. Input data, formulas and filenames are never sent. Only with your optional consent, Refentra sends aggregate counts of actions and outcomes, without input content.
What are the limits?
Maximum amount 1 trillion units; total 100 trillion cents. Up to 100 rows, 50 people, 20 tiers, 100 depreciation years, 1,200 schedule periods, 61 cash flows. IRR range −99% to 1,000% per interval, numerical candidates only. Rates: up to eight decimals. Backup: 1 MiB. CSV formula-leading text gets an apostrophe. Use decimal points, no thousands separators.
Amounts use two decimals in your stated unit. Exact decimal inputs; cent rounding half away from zero. Table sums balance. Largest fractional remainders receive shared cents; equal remainders use row order. No tax, fees, legal entitlement or current prices are inferred.
Non-monetary values are shown with up to ten significant digits. CAGR, fractional-year inflation and IRR use numerical approximations; IRR candidates are not a symbolic proof. CSV keeps the numeric values before display rounding.
E = W × h × d / 1000; C = E × p_kWh
Calculate with your own assumptions
- Enter the inputs
Add each appliance’s watts, average hours per day and operating days per year. Enter your own price per kWh in the currency you choose; the currency label doesn't look up a tariff. Enter decimals with a point and without thousands separators.
- Check a worked example
100 W ×2 h/day ×365 days /1000=73 kWh/year. At 0.2 EUR/kWh the annual cost is 73×0.2=14.60 EUR.
- Interpret and save the result
The table estimates each appliance separately, and the total cost adds up the rounded costs. Review your duty-cycle assumptions before you save the CSV, especially when the rated power differs from the average consumption.
Method, errors and limits
Can I reopen editable inputs from the CSV?
The CSV is a report of the results, not a backup of your inputs. Download the separate JSON input backup before you close the page, then import it into this same tool to edit your assumptions again. Import accepts files up to 1 MiB and checks that the file belongs to this tool. Inputs are not saved automatically.
Which input mistakes should I check?
Enter W, not kW: 1 kW is 1000 W. Hours per day must be 0–24, and days per year must be a whole number from 0 to 366. The price is per kWh, not your whole electricity bill.
What are this model’s limits?
Up to 100 appliance rows. No smart-meter readings, variable tariffs, standing charges or automatic seasonal adjustment. This is a usage estimate based on the power and time you enter.