The basics

Most electricity tariffs charge one flat rate all day. Agile instead passes through (with a markup) what electricity actually costs on the wholesale market at that half hour, for your specific grid region. When wholesale demand is high (typically early evening, when everyone gets home and turns things on), your rate rises. When demand is low and supply is plentiful (often overnight, or on windy days when wind generation is high), your rate falls, sometimes below zero, meaning you're paid to use electricity.

How and when prices are set

Octopus buys electricity a day ahead, based on the wholesale day-ahead auction. New prices for the next day are typically published around 4pm, covering midnight to midnight. That's why Tracktopus shows "Today" prices with confidence all day, but "Tomorrow" often reads "available after ~4pm" until the day's auction result comes through.

Rates are set per region. The UK is split into 14 grid supply point (GSP) areas, and each can have a meaningfully different price at the same half hour, since local network costs and constraints differ. This is why Tracktopus asks for your postcode rather than assuming a single national rate.

Agile vs Flexible Octopus (the standard tariff)

Flexible Octopus is Octopus's standard variable tariff (one rate for the whole day), updated quarterly in step with the Ofgem price cap. Agile trades that stability for volatility: your average day might land close to the Flexible rate, but individual slots can be far cheaper or far more expensive. Tracktopus shows a live "vs SVT" comparison on every price so you can see, slot by slot, whether Agile is winning for you right now.

Whether Agile is worth it depends on how much of your usage you can shift into the cheap windows. Someone who mostly uses electricity at fixed times of day (cooking dinner at 6pm, for instance) gets less benefit than someone who can shift usage (an EV charger, a washing machine, a dishwasher, a home battery) into whenever the price happens to be low.

When are prices usually cheapest?

• Overnight (roughly midnight to 5am) is consistently the cheapest stretch of most days, since demand is low and there's often surplus wind generation with nowhere else to go.
• Late afternoon into early evening (roughly 4pm–7pm) is usually the most expensive window, as national demand peaks.
• Windy, mild days can push prices low, or even negative, at almost any hour, since high wind output plus low heating/cooling demand means more supply than the grid needs.

These are general tendencies, not guarantees. Every region and every day differs. Tracktopus's price trends chart and day/hour heatmap show your own region's actual historical pattern rather than a rule of thumb, which is a better guide for your specific area.

Getting the most out of it

• Check the cheapest-slot tip on the homepage each day. It finds today's best contiguous window automatically.
• Look at tomorrow's prices after 4pm if you're planning to run something the next day.
• Use the historical heatmap to spot your region's recurring cheap hours over the last 7, 30, or 90 days, rather than guessing from a single day.
• Anything you can delay (laundry, dishwashers, EV charging, immersion heaters) is where Agile pays off. Things you can't shift, it won't help much either way.

About this guide

Tracktopus is a personal hobby project with no affiliation to Octopus Energy. This guide reflects how the Agile tariff generally works at time of writing; Octopus's own terms are authoritative. Always check the official Octopus Energy Agile page before making switching decisions.