| Tariff | Import | Export | Net Bill |
|---|---|---|---|
How much you spend on importing electricity, after solar offsets your usage.
| Tariff | Rate | Import kWh | Cost |
|---|---|---|---|
Octopus Flux: Charge your battery during cheap night hours (9p/kWh, typically 2am–5am). Use stored energy during the day instead of importing at 24p/kWh. Saves ~15p/kWh on every kWh you shift.
Octopus Agile: Charge during the cheapest hours (often 5–10p/kWh between 2am–5am). On some days prices go negative! Avoid peak hours (4pm–7pm) where rates can exceed 40p/kWh.
Estimated annual saving from smart charging:
How much you earn from exporting solar to the grid.
| Tariff | Export Rate | Export kWh | Earnings |
|---|---|---|---|
Without a battery, your export is straightforward — whatever solar you don't use goes straight to the grid at your SEG/Outgoing rate.
With Octopus Outgoing (15p/kWh), you earn per year from kWh exported.
💡 Adding a battery could increase your self-consumption from ~40% to ~80%, reducing your export but increasing total savings (you save more by using your own electricity at 24.5p than exporting at 15p).
Octopus Agile: With a battery, you can store solar during the day and export during peak hours (4pm–7pm) when Agile export rates can be highest. Some Agile export rates exceed 30p/kWh during peak demand.
Octopus Flux: Flux pays 15p/kWh export regardless of time. Export during the day from solar surplus. Charge battery at night at 9p/kWh — the spread (15p export − 9p charge = 6p/kWh) provides arbitrage profit.
Potential Agile peak export earnings: /yr (if you shift 30% of export to peak hours)
Finding the cheapest Octopus tariff. Octopus has over a dozen tariffs. Fixed, Flexible, Agile, Go, Cosy, Tracker, and more. The cheapest one depends entirely on when you use electricity. This calculator models your usage against each tariff to find your best option.
Optimising for solar and battery. If you have solar panels and a battery, certain tariffs (like Agile or Cosy) let you charge your battery when electricity is cheap and use it when it's expensive. The calculator shows which tariff maximises savings with your specific setup.
Deciding whether to switch from a fixed tariff. Variable tariffs can be cheaper if you're flexible about when you use electricity, but they carry risk if wholesale prices spike. This calculator shows the potential savings and the worst-case scenarios.
Agile is a half-hourly variable tariff where the price changes every 30 minutes based on wholesale energy prices. It can be very cheap at off-peak times (sometimes even negative!) but expensive during peak hours. It's best for people who can shift usage to off-peak times, especially with a battery.
Cosy is designed for heat pump owners. It offers six hours of cheap electricity per day (split into two three-hour blocks) at about a third of the standard rate. If you have a heat pump and can schedule it to run during the cheap blocks, Cosy can be significantly cheaper than a standard tariff.
Go offers four hours of very cheap electricity overnight (typically 00:30–04:30 at around 7–8p/kWh) with a higher daytime rate. It's ideal for EV owners who charge overnight, or anyone with a battery who can charge during the cheap window.
Yes. Octopus allows tariff switches online without exit fees. You can switch once per day if you want. Many people try Agile for a month, see how it works for their usage, and then decide. No lock-in, no penalty.
Yes. All calculations run in your browser. Your energy usage data never leaves your device.
Octopus's own comparison tool only shows a few tariffs at once and doesn't account for solar or battery storage. This calculator lets you model your complete setup. including solar generation, battery charging, and time-of-use patterns. against all available Octopus tariffs. It's independent, not affiliated with Octopus, and gives you the full picture.
Works offline, no sign-up, no tracking, and no energy company will contact you after using it.
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