Electricity Cost Calculator
Calculate what any appliance costs to run per day, month and year.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
This estimate adds active energy and standby energy across the remaining hours of each day. Daily, monthly, and yearly totals include both; cost per hour is the active-use cost for all selected devices. Enter your USD/kWh rate; fixed fees and taxes are excluded. Monthly energy use and cost share the same selected number of days. Advanced options include appliance count and standby power; fixed utility charges and tiered tariffs are excluded.
Worked example
calculated with the default values below
Power rating 1,500 W · Hours used per day 4 hours · Days used per month 30 days · Electricity price 0.17 USD/kWh · How many of these 1 · Standby power when off 0 W Cost per month 30.60 USD · Energy per day 6.000 kWh · Cost per day 1.020 USD · Cost per year 372.30 USD · Energy per year 2,190.0 kWh · Standby cost per year 0.00 USD · Active-use cost per hour for selected quantity 0.2550 $ · Monthly energy use 180.000 kWh
General background references
Disclaimer
These calculators provide planning estimates only. Building codes, wiring regulations and safety requirements differ by country and change over time, and nothing here replaces a licensed professional or a permit. For structural, electrical or gas work, follow local code and have the installation inspected.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
E_y = 365 × q × (W ÷ 1000 × h + W_s ÷ 1000 × (24 − h)); C_h = W ÷ 1000 × r × q
- W
- Running power (W)
- h
- Daily running hours
- q
- Number of devices
- W_s
- Standby power (W)
- E_y
- Yearly energy (kWh)
- r
- Electricity rate per kWh
- C_h
- Active-use cost per hour for selected quantity
Standby hours = 24 − h. Daily/monthly/yearly totals include quantity q and active plus standby energy; monthly uses entered billing days, annual uses 365 days. C_h covers active use for all selected devices and excludes standby.
Frequently asked questions
How is cost per active hour calculated for multiple devices?
It is rated watts ÷ 1,000 × electricity rate × quantity. This is the active-use cost for all selected units and excludes standby energy. Daily, monthly and yearly totals include both active and standby use; monthly cost uses the entered number of days and annual cost uses 365 days.