ONEEV Cost Guide · May 2026
Is the Octopus EV Tariff Worth It? A Real Cost Breakdown
Octopus Energy says EV drivers can save hundreds a year by switching to Intelligent Octopus Go. We ran the numbers for a family of four driving 6,000 miles a year to see what the saving really looks like.
Quick answer: yes, the Octopus EV tariff can be worth switching to, but for a typical family driving 6,000 miles a year, the realistic saving is closer to £146 per year, not always the £400 to £600 headline figure.
What are we comparing?
There are two tariffs in this comparison. The standard Octopus electricity tariff gives you one flat unit rate throughout the day. Intelligent Octopus Go gives you a much cheaper overnight EV charging rate, but a higher daytime rate.
Standard Tariff
Unit rate: 25.27p/kWh
Standing charge: 44.35p/day
Charging window: Same rate, 24/7
Exit fee: None
Intelligent Octopus Go
Night rate: 8p/kWh
Day rate: 32.72p/kWh
Standing charge: 47.71p/day
Exit fee: £50
The 8p overnight rate is excellent. The trade-off is that the daytime rate is higher than the standard tariff. So the real question is not whether the overnight rate is cheap. It clearly is. The real question is whether the overnight saving outweighs the daytime premium.
The family scenario
For this example, we modelled a family of four with one electric car, driving around 6,000 miles per year. We assumed annual household electricity use of 3,800 kWh and a real-world EV efficiency of 3.5 miles per kWh.
1,714
kWh needed to drive 6,000 miles
90%
of EV charging assumed overnight
3,800
kWh annual home electricity use
The full annual cost breakdown
So what is the actual saving?
The result is a net saving of around £146 per year. That is about £12.17 per month. It is still a saving, but it is more modest than the bigger figures often used in advertising.
The ONEEV verdict
For a typical family doing 6,000 miles a year, the Octopus EV tariff is worth considering. The saving is real, but the biggest benefit comes when you can charge your car overnight and shift other home electricity use into the cheaper window.
Why are the advertised savings higher?
Higher advertised savings usually assume higher annual mileage and more home energy use shifted overnight. If you drive 9,000 miles a year and move a larger percentage of household electricity into the cheap window, the annual saving can rise significantly.
For many UK families driving between 5,000 and 7,000 miles a year, a more realistic saving range is likely to be around £100 to £200 per year, depending on usage habits.
How to increase your saving
Using the delay timer can move regular appliance use into the cheaper rate window.
A couple of overnight washes each week can help reduce daytime electricity costs.
Smart charging only works if the car is connected and ready to be scheduled.
If you have a timer-controlled hot water tank or immersion heater, this could be one of the biggest savings opportunities.
Do you need special equipment?
Yes. You will usually need a SMETS2 smart meter and either a compatible EV or compatible smart home charger. Before switching, check that your car or charger is supported by the tariff.
The bottom line
For a family of four driving 6,000 miles a year, switching to Intelligent Octopus Go saves around £146 per year based on this model. That is not a life-changing amount, but it is still money saved, especially if you already charge at home overnight.
The standing charge difference is small. The exit fee is manageable. The overnight rate is genuinely attractive. So the sensible answer is: switch if your car, charger and lifestyle fit the tariff.
Important note
These figures are based on the tariff rates used in the original article: standard tariff 25.27p/kWh and 44.35p/day; Intelligent Go 8p/kWh overnight, 32.72p/kWh daytime and 47.71p/day. Energy rates can change, so always check the current tariff before switching.
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