Energy Tariff Comparison Calculator

Compare the yearly cost of two energy tariffs using your household’s electricity and gas use. Include both unit rates and standing charges, plus any fees that affect switching.

How to use Energy Tariff Comparison Calculator

1. Choose the currency used for results. 2. Use the same annual kWh totals for both quotes. Enter tax-inclusive unit rates and daily standing charges, and include the relevant fees once. 3. Change a value to update the results, or select Calculate. Review the chart and notes with the total. 4. Use Copy results, Share results or Download result graphic to keep the answer. Shared links include your figures. 5. Reset restores the editable example inputs.

Why use this tool?

The lowest unit rate is not always the lowest bill. A tariff with a higher standing charge can cost more for a low-use home, while a lower unit rate may make a bigger difference in a high-use household. Comparing both quotes against your own kWh totals makes the result more relevant than comparing a headline bill for a typical household. You can also isolate electricity by setting gas use and both gas standing charges to zero.

How the calculation works

Year cost = electricity kWh × electricity unit rate + gas kWh × gas unit rate + (electricity daily standing charge + gas daily standing charge) × days in the year + entered fees. The comparison uses the same usage for A and B. Monthly averages divide each total by 12. Prices are entered in the selected currency. For GBP, 25p/kWh is 0.25 and a 50p daily charge is 0.50. The calculator compares a single rate for each fuel; it does not allocate usage between Economy 7 or other time-of-use registers.

Example

For 3,000 electricity kWh and 10,000 gas kWh, the example A rates give £1,742 including 365 days of standing charges. The example B rates give £1,750.25. A is £8.25 lower under those illustrative prices, even though B’s electricity unit rate is lower.

Practical tip

Check whether an exit fee is genuinely payable for the comparison you are making. Do not add a switching fee more than once or mix VAT-inclusive and VAT-exclusive quotes.