Fixed vs Variable Energy Tariff Calculator
Compare a real fixed quote with October–December 2026 variable reference rates at your own consumption. Annual totals hold both sets of rates for 365 days; they do not predict future quarterly caps.
In our illustrative comparison, fixed costs are £1,592.95 and variable costs are £1,723.61 for a year with no switching fee. This holds entered rates unchanged; it is not a prediction or an available tariff offer.
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A fixed quote can give rate certainty during its term, but it is not automatically cheaper. Compare the whole cost at your consumption and check contract length, switching charges and future early-exit terms.
Understanding the break-even point between fixed vs variable tariff options helps you decide whether locking in makes sense. Enter your energy details below to see which tariff type could save you money, then check your annual cost with the electric bill calculator.
Uncheck for electricity only. A connected gas supply still has standing charges when usage is zero.
Default rates: 1 October–31 December 2026. Ofgem GB averages for Direct Debit and single-rate electricity: electricity 26.32p/kWh + 54.83p/day; gas 7.97p/kWh + 29.68p/day.
These published prices already include applicable tax. Use the tax-inclusive rates from your own bill or quote for your region, payment method and tariff. Northern Ireland and multi-rate tariffs need their own rates.
Annual figures hold the entered rates for 365 days. They are an illustration, not a forecast of future quarterly caps or your Direct Debit payment. Fixed-deal figures are illustrative until you enter an actual quote.
Ofgem source · Checked 12 October 2026
Fixed Tariff (illustrative quote)
Unit Rates (p/kWh)
Standing Charges (p/day)
Only fees payable now, such as leaving your current deal. Do not include a new deal’s future early-exit fee unless you expect to pay it during this comparison.
Variable Tariff
Unit Rates (p/kWh)
Standing Charges (p/day)
Tip: Variable caps change quarterly. This comparison holds both sets of entered rates for 365 days; future variable rates are unknown.
Your Annual Usage
Ofgem's GB medium benchmark from July 2026: 2,500 kWh electricity and 9,500 kWh gas. Use your actual annual kWh.
Fixed Tariff
Cheaper£132.75 per month
Variable Tariff
£143.63 per month
Savings Summary
Fixed is cheaper at these rates by £130.66 per year
That's £10.89 per month
There is no positive break-even at this fuel mix: the cost lines do not cross at positive usage.
Both totals hold entered rates for 365 days. The difference is a scenario result, not a guaranteed saving or a prediction of future variable caps.
Cost Breakdown
| Component | Fixed | Variable |
|---|---|---|
| Electricity usage | £625.00 | £658.00 |
| Gas usage | £665.00 | £757.15 |
| Electricity standing charge | £200.75 | £200.13 |
| Gas standing charge | £102.20 | £108.33 |
| Total Annual Cost | £1,592.95 | £1,723.61 |
How to compare fixed and variable energy tariffs
Use the same annual consumption and connected supplies for both tariffs. For each fuel, multiply kWh by its pence-per-kWh price and add 365 daily standing charges, dividing pence by 100. Add any fee payable now to take the fixed option once.
The starting fixed prices are illustrative: electricity 25p/kWh and 55p/day, gas 7p/kWh and 28p/day. They are not an available offer. Replace them with an actual tax-inclusive quote. Variable defaults are October–December 2026 GB Direct Debit averages; regional prices and other payment methods differ.
Worked comparison: switching fees can change the result
Examples use 2,500 kWh electricity and 9,500 kWh gas. Both sets of rates remain unchanged for 365 days. The only difference between rows is a fee payable now to take the fixed option.
| Switch fee | Fixed total | Variable total | Lower scenario cost |
|---|---|---|---|
| £0.00 | £1,592.95 | £1,723.61 | Fixed by £130.66 |
| £150.00 | £1,742.95 | £1,723.61 | Variable by £19.34 |
Include the total you expect to pay now, summed across relevant fuels. A new deal's future early-exit fee is conditional and should not automatically be treated as a current charge. Check both contracts and whether a fee applies to either route. Discounts, credits and other charges are excluded unless you adjust the comparison separately.
What a break-even usage level means
The tool scales the entered electricity and gas consumption together, preserving their ratio. It finds where the difference in unit costs offsets the difference in standing charges and the switching fee. Electricity and gas kWh are not interchangeable, so the result shows each fuel separately.
Equal cost lines match at every proportional usage level. Parallel lines with different fixed charges never meet. Other pairs can meet only at zero or at negative usage, so there is no positive threshold. If both entered consumptions are zero, enter a positive amount to define a fuel mix.
A cheaper scenario is not guaranteed savings
Future variable caps are unknown. A fixed tariff may provide price certainty during its contract, but it is not necessarily the lowest eventual bill. Compare alternative variable rates, actual consumption, contract length, what happens on expiry, payment method, region and the cost of leaving early.
A 365-day comparison is less suitable for a different term or changing usage. Multi-rate tariffs need separate peak/off-peak calculations, and Northern Ireland needs its supplier rates. Use the energy-bill calculator for a single-tariff estimate and the standing-charge tool to examine daily costs.
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