Guide updated 11 July 2025 – live rates change daily, so always grab a fresh quote.
Full methodology and latest figures
Quick answer
For a typical household that just wants a plain, set-and-forget deal, the 12-Month Fixed “June 2025 v1” tariff is currently Octopus Energy’s cheapest mainstream option at 25.6 p/kWh for electricity and 6.07 p/kWh for gas in South Wales (roughly 3 % below the July price-cap) Get this offer.
If you have a smart meter and don’t mind daily price changes, Octopus Tracker beats that on most days – averaging 21.9 p/kWh electricity and 5.6 p/kWh gas in June 2025 – but it can spike in winter, so it suits risk-tolerant customers.
For electric-vehicle owners, nothing touches Octopus Go (8.5 p/kWh between 00:30-05:30) or Intelligent Octopus Go (7 p/kWh in a flexible six-hour window).
How Octopus sets its prices
- Standard variable (Flexible Octopus) follows – and undercuts – Ofgem’s quarterly price cap (25.7 p/kWh electricity, 6.3 p/kWh gas from 1 July 2025).
- Fixed tariffs lock in unit rates for a year but carry no exit fees, so you can leave if prices fall.
- Smart tariffs (Tracker, Agile, Go, Cosy, Flux) rise and fall with wholesale markets or time-of-day signals; they need a smart meter.
Because wholesale prices now fluctuate hourly, “cheapest” depends on how and when you use energy.
Snapshot of headline tariffs (11 July 2025)
| Tariff | Ideal customer | Elec. unit rate | Gas unit rate | Key points |
|---|---|---|---|---|
| 12-Month Fixed (June v1) | Anyone wanting certainty | 25.59 p/kWh | 6.07 p/kWh | No exit fees; rates fixed for a year. |
| Flexible Octopus | “Set-and-forget” customers | 25.7 p/kWh | 6.3 p/kWh | Rises/falls with price cap. |
| Octopus Tracker | Smart-meter users willing to ride the market | Avg 21.9 p/kWh† | Avg 5.6 p/kWh† | Rates published daily at 16:00; can spike in cold snaps. |
| Agile Octopus | Tech-savvy homes able to shift load | 20.7 p/kWh (current daytime avg) | n/a | Half-hour rates; cheap midday, pricey 16:00-19:00. |
| Octopus Go | EV or battery charging | 8.5 p/kWh (00:30-05:30) then 28.1 p | n/a | Needs smart meter & EV. |
| Intelligent Go | EVs that let Octopus schedule charging | 7 p/kWh in a six-hour smart window | n/a | Compatible car/charger required. |
† 30-day average. Prices include 5 % VAT; standing charges vary by region.
Which tariff will really cost you least?
1. Standard usage (no EV, no heat pump)
- Cheapest predictable bill: the 12-Month Fixed. Its unit rates are lower than Flexible and you can walk away if prices tumble further.
- Potentially cheaper, but variable: Tracker. Over the past 12 months it’s beaten Flexible by ~3-4 p/kWh on average, but during cold snaps it has peaked above 40 p/kWh.
2. High night-time consumption (EV, battery or heat pump)
- Go / Intelligent Go slash charging costs to single-digit pence; even with a higher daytime rate, EV drivers using ~70 % of their energy at night pay hundreds less per year than on Fixed or Flexible.
3. Able to shift appliance use
- Agile Octopus posts half-hourly prices 4 pm the day before. Mid-day July rates barley 10–12 p/kWh; evening peaks can exceed 30 p. If you can run washing machines, dishwashers and immersion heaters off-peak, Agile often undercuts every other tariff.
4. Off-grid-friendly homes with solar + battery
- Cosy/Flux combinations can pay export rates up to 24 p/kWh and cheap import overnight. Cheapest overall cost depends on solar yield; speak to Octopus for a bespoke quote.
How to pick the cheapest option for you
- Check your split between day, night and evening usage. Smart-meter data or plug-in monitors make this easy.
- Match that profile to the tariff. High night use → Go; all-day steady use → Fixed; variability OK → Tracker or Agile.
- Factor in regional rates. Octopus publishes 14 regional prices; London is usually ~0.8 p higher than Northern Scotland.
- Remember the standing charge. A super-low unit rate can be wiped out if the standing charge is 15 p/day higher.
- Review quarterly. Octopus lets you switch tariffs without penalty, so reassess when the price cap moves or your lifestyle changes.
Bottom line
No single Octopus tariff is “the cheapest” for everyone.
- Fixed wins if you value stability.
- Tracker can be the absolute lowest cost but you must accept risk.
- Go / Intelligent Go are unbeatable for EV charging.
- Agile is ideal for tech-savvy households that can automate appliance times.
Grab a smart meter, look at your consumption pattern, and run the numbers – Octopus’ no-exit-fee policy means you can always hop to the cheaper tentacle when it appears.
