Your year on each tariff
What your saving buys
Month by month
Keep SunSums free
This tool is free and has no ads. If it helped, here are three ways to say thanks.
How it works
For each month we build a typical day, half hour by half hour: your home's use, the car charging in the cheapest slots, the heat pump, and the sun on your roof. The battery fills from spare solar and, when it pays, from cheap power, then covers the dear hours. If you let it, it also sells spare charge at the evening peak. Each tariff is paired with whichever export tariff pays you more. With your own data, we price every half hour you actually used.
Prices used
Octopus's published prices for your region on 1 October 2026, including VAT. Agile uses the average price for each half hour of each month from October 2025 to September 2026.
| Tariff | Cheapest | Usual | Dearest | Standing | Needs |
|---|
Good to know
- Agile prices change every day. A cold, still winter can cost a lot more than the average shown.
- Intelligent Go needs a compatible car or charger. Intelligent Flux needs a compatible battery. Cosy needs a heat pump.
- Check your tariff's rules before selling battery power back to the grid.
- With your own data we keep your usage as it is. Moving the car or the dishwasher to the cheap hours would save more.
- Electricity only. Gas isn't counted.