Tariff comparison calculator
Compare whole-bill costs for your current and proposed energy tariff.
Calculator
Whole-bill tariff comparison
The current side is pre-filled with the Ofgem price cap for the region and payment method you choose. Enter the proposed tariff's rates from the supplier's tariff information. The calculator compares the entered rates as though they applied for the selected comparison period; it does not predict future variable rates.
Your usage
Default: Ofgem typical use.
Enter 0 if you have no gas supply.
Enter every rate for both tariffs and correct any highlighted fields. Results are hidden until all inputs are valid.
| Per year | Current or capped | Proposed |
|---|---|---|
| Electricity usage cost | — | — |
| Gas usage cost | — | — |
| Standing charges | — | — |
| Ongoing annual cost (no incentives) | — | — |
| One-off credit | – | — |
| Total first-year cost | — | — |
- Difference per year
- —
- Difference per month
- —
- Net difference over the period (inc. credit)
- —
- Exit fee (not included above)
- —
- Effective break-even point
- —
Assumptions used
- Annual cost = electricity usage cost + electricity standing charge + gas usage cost + gas standing charge.
- Standing charges use 365 days a year. Unit rates and standing charges include VAT when taken from the Ofgem cap.
- Single-rate electricity only. Day/night and time-of-use rates are not modelled.
- Both tariffs are compared at the entered rates for the whole comparison period. Variable rates can change each quarter.
- The one-off credit is subtracted once, in the first year. The exit fee is shown separately and only counts towards break-even.
- Break-even is the number of months of lower bills needed before any credit, less the exit fee, turns into a net saving.
- Default current rates: Ofgem price cap for July 2026 - September 2026, England, Scotland & Wales average, Direct Debit.