How it works
Estimate energy and variable usage cost from appliance power and time. Fixed fees, tax rules and changing tariffs are excluded.
cost = W/1000 × hours × days × unit price
Worked example
Show example inputs and result
Appliance power: 1,500 · Hours per day: 2 · Days: 30 · Price per kWh: 0.25.
- Usage cost
- 22.5
- Energy
- 90 kWh
Questions and answers
Why are some results rounded?
Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.
Are my inputs sent to a server?
The calculator processes inputs in your browser. Its code does not send your values to a server.
Method reviewed: October 8, 2026 · Methods & accuracy