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Electricity Cost Calculator

Calculate your electricity costs per day, month and year based on your usage and unit rate.

Last reviewed 15 August 2026

Your details

Calculator inputs

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When to use this calculator

  • Before switching supplier, upgrading equipment or comparing energy-saving changes.
  • When you want to test different usage or price scenarios quickly.
  • When you need a simple estimate before requesting installer or supplier quotes.
  • When a tariff is about to change and you want to model the bill impact.

A realistic South Africa planning example

Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.

A realistic South Africa planning example
InputValue
Usage Per Day (kWh)15
Price Per kWh (R)4.5 kW

After entering these figures, review daily, monthly and annual together rather than in isolation. Then rerun the tool with one input adjusted.

How to read your results

Daily

The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.

Monthly

The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.

Annual

The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.

Method & assumptionsAuthoritative sources

This calculator multiplies the daily kilowatt-hour use you enter by the unit rate you enter. It does not add a standing charge, capacity charge or tax. If your bill quotes a tax-inclusive unit rate, enter that figure to estimate daily, monthly and annual energy cost. Usage is treated as constant across the year, which is a planning simplification.

Common mistakes

  • !Using an assumption that is not supported by a current local quote, bill, statement or official source.
  • !Treating a generic estimate as a lender, provider, payroll or tax authority decision.
  • !Mixing monthly and annual inputs without converting them consistently.
  • !Testing only one scenario instead of checking how a cautious assumption changes the result.

What to do next

  • Run a second scenario with a cautious assumption so you can see the downside clearly.
  • Compare the result with the related calculators below before making a decision.
  • Check current local rules, eligibility and provider terms before applying or committing money.
  • Keep a record of the assumptions so you can update the estimate when a quote, bill or pay figure changes.

Frequently asked

Daily cost is kWh per day multiplied by the unit rate you enter. Monthly and annual figures scale that daily cost. Standing charges and tax are not added, so use the unit rate as it appears on your bill if you want an all-in energy unit cost.

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