---
title: "Appliance Running Cost Calculator | Lightnest Market"
description: "What an appliance costs to run per day, month and year, from its watts, hours of use and your price per kWh, with typical wattage ranges to start from."
url: https://lightnestmarket.shop/
---

# Appliance running cost calculator

How much does the kettle, the heater or the old fridge in the garage really cost to run? Enter its watts, how long it is on, and the price per kWh from your bill.

## How the running cost is worked out

Find the wattage on the appliance's label or in its manual. If only the current is given, multiply the amps by your supply voltage: 3 A × 120 V = 360 W. Then estimate how long it runs each day and on how many days a year, and take the price per kWh from your electricity bill.

kWh a day = watts × hours a day ÷ 1,000
kWh a year = kWh a day × days used a year
Cost a year = kWh a year × price per kWh

These are the steps the U.S. Department of Energy's Energy Saver guide sets out. The appliance list starts you from the middle of a typical nameplate range. A nameplate gives the most an appliance can draw, and fridges, heaters and pumps switch on and off, so count only the hours they really run, or measure with a plug-in energy meter.

## Sources

- U.S. Department of Energy, Energy Saver: [Estimating Appliance and Home Electronic Energy Use](https://web.archive.org/web/20250601024356/https://www.energy.gov/energysaver/estimating-appliance-and-home-electronic-energy-use) (archived copy, June 2025): the daily kWh, yearly kWh and yearly cost formulas, and the amps × volts example.
- Utah Division of Water Rights, [Typical Wattages of Various Appliances](https://www.waterrights.utah.gov/sustainability/appliance_wattages.pdf) (credited there to the EPA): the nameplate wattage ranges in the appliance list.

## More calculators for a well-lit home

Bulbs, standby, units and batteries.

- [LED vs incandescent](https://lightnestmarket.shop/led-vs-incandescent-savings/): Yearly savings, payback time and the cost over a whole LED lifetime.
- [Standby power cost](https://lightnestmarket.shop/standby-power-cost-calculator/): Add up what your devices draw while they wait, device by device.
- [kWh cost converter](https://lightnestmarket.shop/kwh-cost-converter/): kWh, Wh, MJ, Btu and therms, prices per unit, and the cost of any amount.
- [Power bank capacity](https://lightnestmarket.shop/power-bank-capacity-calculator/): mAh to Wh, realistic phone charges, and the 100 Wh and 160 Wh flight limits.

## Recommended

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### CleanTempMail

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### WebTraceCheck

A message about an "energy rebate", or a suspiciously cheap deal on bulbs or power banks from a shop you do not know? WebTraceCheck's free DNS and domain lookup shows the details behind an unfamiliar domain, and its disposable cloud browser opens links on an isolated desktop that is deleted after each session.

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[Try WebTraceCheck](https://webtracecheck.com/)

## Questions

**Why isn't the monthly cost the daily cost times 30?**

The daily cost is for a day the appliance is used. The monthly figure spreads the yearly cost evenly over 12 months, so it already allows for the days it stays off.

**Which price per kWh should I use?**

The energy rate on your bill. Fixed daily or monthly charges are paid whatever you use, so leave them out when you compare appliances.

**Does switching off at the wall save more?**

Only the standby part. The standby power calculator adds up what devices draw while they wait, which is small per device but runs every hour of the year.