Is a time-of-use EV tariff cheaper than the price cap?
Would an EV tariff with cheap nights beat the standard capped tariff for your home and car together? The catch: daytime rates on these tariffs are often higher than the cap, so they only win if enough of your use moves to the night. Results update as you type.
Your inputs
Ofgem typical medium use
Higher if you run appliances overnight
Ofgem cap average, Oct–Dec 2026
Ofgem cap average, Oct–Dec 2026
Intelligent Octopus Go, from 6.5p (Octopus Energy, checked 31 Oct 2026)
Placeholder: enter the day rate from your quote
Placeholder: enter the figure from your quote
Shown for reference only, not deducted
Result
Adjust inputs to calculate
Breakdown
Cumulative difference over 5 years
Positive means the time-of-use tariff is cheaper. Prices held flat.
What your result means: if it says the time-of-use tariff saves money a year, switching should pay on these numbers. If the standard capped tariff is cheaper, you're not moving enough use into the cheap hours yet. Charging the car overnight is usually what tips it.
Estimates for information only, not financial advice. Prices, grants and rates change, so check them with the supplier or installer before you decide. Get at least three quotes from MCS-certified installers. See our terms.
How we calculate
- EV electricity: miles ÷ miles per kWh × (1 + charging losses).
- Standard: (home + EV kWh) × capped unit rate + 365 × standing charge.
- Time-of-use: cheap-hour kWh × cheap rate + other kWh × day rate + 365 × standing charge.
- Break-even: the EV mileage (or off-peak share) where both tariffs cost the same, with everything else fixed.
- Smart tariffs can add extra cheap slots when the supplier controls charging. That is not modelled, so this is conservative.
Sources and last updated
All figures checked on 27 October 2026 unless stated. Every default can be changed.
| Figure | Default | Source (date) |
|---|---|---|
| Cap unit rate and standing charge | 26.32p, 54.83p/day | Ofgem price cap, 1 Oct–31 Dec 2026 |
| Cheap rate | 6.5p | Octopus Energy: Intelligent Octopus Go (“smart charge eligible cars from only 6.5p/kWh”, checked 31 Oct 2026) |
| Day rate and standing charge | 28p, 54.83p — placeholders | Not published as a single figure: Octopus shows them only in a quote for your postcode. |
| Typical home use | 2,700 kWh | Ofgem typical domestic consumption values — not re-checked today |
Frequently asked questions
What about Guernsey?
The Ofgem cap does not apply in Guernsey. Guernsey Electricity's Standard tariff is 26.01p/kWh, and its Super Economy 12 tariff has a low rate of 13.12p/kWh (checked 3 Oct 2026). Put those into the capped and cheap-rate boxes, with Guernsey Electricity's own day rate and standing charges, to compare.
Is a time-of-use tariff worth it without an EV?
It depends on the day rate. With the placeholder 28p day rate and 20% of home use at night, the time-of-use tariff is still about £71 a year cheaper with no EV. With a day rate of about 31.3p or more, the cap wins unless you move more use overnight. Enter the day rate from your own quote.
How many miles do I need to drive?
On the default rates, an EV doing any regular mileage tips it in favour of the time-of-use tariff: the calculator shows the break-even mileage for your figures.
Does this include the price cap change on 1 January 2027?
No. Ofgem announces the next cap on 25 November 2026. Update the cap figures then.
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