Intelligent Octopus Go 6-Hour Charge Cap Explained (2026)

The Intelligent Octopus Go six-hour cap, paired with the new Charge Cap toggle, goes live in March 2026 and changes how much super-cheap EV charging each home gets in any 24-hour period. This guide walks through exactly what the cap counts, what the toggle does, who actually feels it, and what to do if a single overnight session needs more than six hours of smart charging.

The Charge Cap is a 6-hour ceiling on EV smart charging at Intelligent Octopus Go's discounted rate. Before the cap, IOG could schedule as many smart slots as it took to hit your target charge — and the cheap rate applied to every one of them. From the March 2026 rollout, the cheap rate stops after the first six hours of car charging in any 24-hour window. Anything beyond that is billed at the standard daytime (Boost) rate.

Two things make the rule less harsh than it sounds. First, the cap applies only to EV smart charging — the rest of the home keeps its 11:30 pm-5:30 am whole-home off-peak window untouched. Second, the new Charge Cap toggle in the Octopus Energy app gives a clean opt-out from any peak-rate overflow: turn it on and the platform simply stops charging at six hours rather than spilling into peak rates.

Octopus first announced the cap in December 2025 with a January 2026 enforcement date, then pushed the launch back while it completed internal testing. The current public position is that the cap and the Charge Cap toggle launch together in March 2026, with notice to customers before they go live. Existing IOG customers' headline off-peak rates were held during the transition while new sign-ups saw higher pricing.

The cap is a follow-on to the April 2026 EV-rate reductions: the November 2025 Budget removed roughly £150 of green levy costs from household electricity, and Octopus passed that through to IOG off-peak rates from 1 April 2026 — taking the off-peak rate to around 5.49p/kWh in most regions, a cut of roughly 3.5p/kWh. We covered the broader rate reset in our November 2025 Budget for EV drivers guide.

The toggle lives in the Octopus Energy app under device settings for your linked car or charger. It has two states, and the choice is purely about how you want trade-offs handled when the 6-hour cheap window isn't enough.

The right setting depends on how flexible the next morning needs to be. A driver with a stable commute and modest daily mileage rarely needs more than six hours of charging, so leaving Charge Cap on costs nothing and removes the risk of an accidental peak-rate session. A driver who occasionally arrives home almost empty before a long trip the next morning may prefer Charge Cap off for that night, accepting the partial peak-rate bill rather than the half-charged car.

This was the single most-confusing detail in the original announcement: the six hours are not calendar-day-based. The window runs from midday to midday, so any smart charging logged between 12:00 and the next 12:00 counts toward a single 6-hour allowance.

That matters in two practical scenarios. A long Sunday evening session that runs from 9 pm to past midnight is one continuous use of the allowance — it does not split across calendar days. A short top-up at 11 am the next day (before the midday roll-over) still falls inside the same allowance window. A second top-up at 1 pm, on the other hand, starts a fresh six hours.

Some early readings of the policy concluded that customers were guaranteed 6 hours of car charging plus the 6-hour 11:30 pm-5:30 am off-peak window, for an effective 12 hours of cheap car charging. That is not how the cap works.

The 11:30 pm-5:30 am window is a whole-home off-peak window — every appliance in the house, including the EV charger, is billed at the off-peak rate during those six hours. But car charging consumes the 6-hour smart-charging allowance whether it lands in that window or outside it. Once a session crosses six hours of car charging in a 24-hour cycle, additional car kWh are billed at the Boost rate — even if they fall between 11:30 pm and 5:30 am. The cap is about the car, not about the clock.

Octopus's headline stat is that around 80% of IOG charging sessions already complete in under six hours. The 20% who routinely exceed that fall into three buckets:

A useful arithmetic check: at 7.4 kW, six hours delivers roughly 44 kWh. If your typical "plug in empty, charge to 80%" target asks for more than 44 kWh, you should expect the cap to bite without intervention.

The simplest mitigation is rarely needed: most drivers are inside the 80% who already fit comfortably. For the rest, four approaches work in combination.

Bump Charge (sometimes shown as "Max charge" on Ohme, "Boost" inside the Octopus app) is the manual override that pulls the car off the smart scheduler and charges at the highest power available. It is always billed at the peak or standard rate — never at the discounted IOG rate, regardless of time of day.

The right scenario for Bump Charge is rare and specific: you arrived home unexpectedly low, you need to leave again in an hour, and you genuinely need the kWh more than you need the savings. For anything less time-pressured, Charge Cap off is usually cheaper because the first six hours of the overflow session are still at the discounted rate.

The 6-hour cap is best read alongside the rate cut Octopus rolled out on 1 April 2026. The off-peak rate fell to approximately 5.49p/kWh in many UK regions — a reduction of around 3.5p/kWh, or up to 39% depending on starting point. Combined, the two changes mean a typical IOG user pays significantly less per kWh for the kWh they get, but is more carefully metered on how many of those kWh count as "off-peak."

The headline saving still stacks up. A 10,000-mile-a-year EV at 4 mi/kWh consumes 2,500 kWh annually. At 5.49p/kWh that's £137; at the standard daytime rate of around 32p/kWh that would be £800 — a £660 difference. High-mileage drivers can save over £1,400 a year versus a standard variable tariff, even with the cap in force. We model the cost-per-mile maths in detail in our home charging cost guide.

For the 80% of drivers whose sessions already fit comfortably inside six hours, the cap is invisible — there is no reason to switch. For drivers who consistently exceed six hours, the practical question is whether to (a) stay on IOG and accept occasional Charge Cap-off peak overflow, (b) stay on IOG with Charge Cap on and accept the car occasionally falling short of target, or (c) move to a fixed-window EV tariff like OVO Charge Anytime or the simpler Octopus Go.

OVO Charge Anytime currently runs an anytime-charging rate without a per-day allowance — we covered the trade-offs in Intelligent Octopus Go vs OVO Charge Anytime. The simpler Octopus Go tariff has a fixed 4-hour cheap window with no smart slots and no cap — see our Octopus Go vs Intelligent Octopus Go comparison for the decision framework.

For most people, the right answer is still IOG — the discounted rate is materially better than the fixed-window alternatives, and the cap is generous enough that only outlier sessions are affected. Our UK EV tariff comparison ranks the eight major options on rate, off-peak window, and eligibility.