What It Costs to Charge an EV for 400 Miles
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The same 400 miles of driving can cost you anywhere from under £10 to well over £90, and the difference has almost nothing to do with which car you drive. It comes down entirely to when and where you charge.
The three scenarios
The figures below all use the same average efficiency assumption (about 3.3 miles per kWh, matching the conversion Zapmap itself publishes for its rapid-charging figure), so the three rows are directly comparable rather than each quietly assuming a different car.
| Method | Rate | Cost per mile | Cost for 400 miles | Source (checked 13 Aug 2026) |
|---|---|---|---|---|
| Standard home rate, any time | ~26p/kWh | ~7.8p | ~£31 | Ofgem price cap, Jul-Sep 2026 average |
| Off-peak EV tariff, overnight | 8p/kWh | ~2.4p | ~£9.60 | Octopus Intelligent Go, 11:30pm-5:30am window |
| Public rapid charging | ~80p/kWh | ~24p | ~£96 | Zapmap charging price index, 50kW+ PAYG average |
Standard home electricity, any time of day. Charging on a normal variable domestic rate - without an EV-specific tariff - means paying whatever the general household rate is, no matter when you plug in.
An off-peak EV tariff, charging overnight. The same 400 miles drops to around £9.60 - well under a third of the standard-rate cost, for identical driving. Other suppliers run similar EV-specific overnight tariffs; the exact pence-per-kWh figure varies by supplier and region, but the shape of the saving is consistent.
Public rapid charging. The most expensive option by a wide margin - roughly ten times the off-peak cost for the same 400 miles. It still makes sense for topping up on a long journey; relying on it as your everyday method is by far the most expensive way to run an EV.
Why the gap is this big
It isn’t really about the car - it’s about which electricity market you’re buying from. Standard variable rates price electricity the same regardless of when you use it. Off-peak EV tariffs exist because energy suppliers want to shift demand into low-usage overnight hours, and pass a genuine discount back to you for doing it. Public rapid chargers are priced for convenience and speed, not for cost efficiency - you’re paying for not having to plan ahead.
What this actually means for your setup
If you’re only ever charging on standard rates, switching to a dedicated EV tariff is very likely the single biggest cost saving available to you - bigger than most hardware decisions. It does usually require a smart charger capable of scheduling or communicating with your supplier to charge during the off-peak window automatically, rather than relying on you remembering to plug in at the right hour every night.
If you’re mostly relying on public rapid charging because home charging isn’t set up yet, that’s worth treating as a temporary state rather than the long-term plan - the cost difference compounds fast over a year of normal driving.
Keep this current
Energy prices move. Ofgem’s price cap updates every quarter, and EV tariff and rapid-network rates shift more often than that - the figures above were checked directly against Ofgem, Octopus, and Zapmap on 13 August 2026, not carried over from an older estimate. See our editorial standards for how we keep pages like this updated, and treat these as a snapshot rather than a permanent quote for your own budget. Your own car’s efficiency (miles per kWh) will also shift the exact numbers, though the proportional gap between the three scenarios holds regardless of what you drive.
Common questions
Do I need a smart charger to get off-peak rates?
In most cases, yes, or at least a charger that can be scheduled. Off-peak EV tariffs work by charging a low rate during set hours - to actually benefit, something needs to make sure charging happens inside that window, whether that's the charger's own scheduling, your car's app, or the tariff supplier's own smart-control system. Plugging in whenever you happen to arrive home, on a standard tariff, won't automatically capture the saving.
I don't have a driveway - can I still get cheap overnight rates?
Yes, in principle, once you have a home charging setup - the tariff is tied to your electricity account and meter, not to where the car physically sits. The bigger barrier for driveway-less homes is usually the charger installation itself (see our cross-pavement charging guide), not tariff eligibility.
Does charging speed - 7kW versus 22kW - change the cost?
Not directly. The pence-per-kWh rate is what determines cost, and that's set by your tariff, not your charger's power rating. A faster charger fills the battery quicker, which can matter for fitting into a short off-peak window, but it doesn't change the price of each unit of electricity.
Is charging from solar panels actually free?
Broadly yes for the portion of a charge that solar genuinely covers in real time, since you're not buying that electricity from the grid at all - though most home solar systems can't fully power a fast EV charge on their own, especially outside summer daylight hours, so it typically supplements rather than replaces a grid-based charging strategy.