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Free · Agile · Go · Cosy · Fixed — electricity & gas

Know when electricity is cheap. Every half hour.

Connect your Octopus API key and get a live dashboard of your tariff's prices, your real usage and costs including standing charges, cheapest-window forecasts and price alerts.

Get started — it's free See a live demo →

Read-only API access · no password, no smart-meter hardware, no card.

Price now · London

Agile Octopus · inc VAT · 20 Oct 2026, 13:10

30.94

p/kWh · Peak · until 13:30

00:00–00:30 — 28.38p 00:30–01:00 — 28.30p 01:00–01:30 — 27.50p 01:30–02:00 — 28.38p 02:00–02:30 — 28.18p 02:30–03:00 — 27.88p 03:00–03:30 — 28.08p 03:30–04:00 — 27.98p 04:00–04:30 — 28.02p 04:30–05:00 — 27.34p 05:00–05:30 — 28.31p 05:30–06:00 — 27.77p 06:00–06:30 — 30.66p 06:30–07:00 — 32.36p 07:00–07:30 — 32.64p 07:30–08:00 — 35.85p 08:00–08:30 — 34.70p 08:30–09:00 — 33.35p 09:00–09:30 — 32.75p 09:30–10:00 — 32.81p 10:00–10:30 — 31.65p 10:30–11:00 — 30.94p 11:00–11:30 — 31.14p 11:30–12:00 — 30.80p 12:00–12:30 — 29.95p 12:30–13:00 — 30.18p 13:00–13:30 — 30.94p 13:30–14:00 — 30.57p 14:00–14:30 — 29.54p 14:30–15:00 — 28.74p 15:00–15:30 — 31.91p 15:30–16:00 — 33.56p 16:00–16:30 — 48.88p 16:30–17:00 — 50.06p 17:00–17:30 — 49.76p 17:30–18:00 — 50.30p 18:00–18:30 — 50.38p 18:30–19:00 — 50.56p 19:00–19:30 — 38.04p 19:30–20:00 — 37.94p 20:00–20:30 — 33.35p 20:30–21:00 — 32.63p 21:00–21:30 — 32.80p 21:30–22:00 — 31.35p 22:00–22:30 — 30.26p 22:30–23:00 — 27.53p

TodayTomorrow23:30

Best 3h window → today 13:00–16:00 · 30.88p avg

How it works

Set up in two minutes

No installation, no hardware, nothing to configure on your meter.

01

Create a free account

An email and a password — that is all we keep about you. It secures your connection and usage history.

02

Paste your API key

Read-only, from your Octopus dashboard under Personal details → API access. We detect your meters, tariff and region — nothing else to type.

03

Watch the pennies

Live prices, what you actually spent, and a nudge before the expensive hours start.

Features

What you get

Live half-hourly prices

Every settlement period for today and tomorrow, the moment Octopus publishes it.

Cheapest-window finder

The cheapest run of consecutive half hours still to come — 30 minutes to 6 hours.

Usage and real costs

Your smart-meter readings priced against your actual tariff, standing charge included.

Alerts

Peak starting soon, plunge pricing, cheap windows, or a price threshold you pick.

Usage profile

Your average half-hourly shape, so you can see which habits are costing you.

Gas too

Gas unit rates and standing charges alongside electricity, on the same dashboard.

Prices and guides

Start where you are

Every region, every current Octopus tariff, and plain explanations of the bits of a UK energy bill nobody ever explains.

Your region

All fourteen regions →

Octopus tariffs

Every tariff explained →

Guides

All guides →

FAQ

Questions

Is it really free?

Yes. Live prices, the cheapest-window finder, your usage and costs, and alerts are all free, with a year of history.

Is my API key safe?

We only ever read with it — your tariff, your meters and your readings, nothing else. Treat it like a password, because it identifies you to Octopus: revoke it from your Octopus dashboard whenever you like, and delete everything we hold in one click.

Do I need a smart meter?

Not for prices — those work for everyone. Usage and cost figures need a smart meter sending half-hourly readings to Octopus.

Which tariffs are supported?

Agile, Go, Cosy, Flux and Snug, plus Flexible and the current Fixed products, for electricity and gas. Whatever the tariff shape, prices land on the same half-hourly grid.

Which region am I in?

Great Britain has fourteen electricity regions, and your unit rate depends on yours. It is the first two digits of the MPAN on your electricity bill, and it is detected automatically if you connect an Octopus account.

Are you Octopus Energy?

No. halfhourly.uk is an independent tool built on the public Octopus API. It is not affiliated with, endorsed by, or connected to Octopus Energy.

Stop guessing when power is cheap.

Free to use, and you can delete everything in one click.

Get started — it's free