What's the cheapest time to use electricity in the UK?

Short answer first, because you came here for one: it depends entirely on your tariff.

On a standard variable or fixed tariff, which is what most households are on, you pay the same price per unit at 3am as you do at 6pm. There is no cheapest time. Running the dishwasher overnight saves you nothing, and you can stop setting alarms.

On a time-of-use tariff, the gap between the cheap hours and the rest of the day is big enough to matter. One evening this week, I checked live Agile prices in Yorkshire: the same washing machine cycle would have cost 31p started at teatime, or 13p started later on. Same wash. Same machine. Different time.

So the useful question is: which tariff are you on, and when are its cheap hours?

Cheap hours on the main UK time-of-use tariffs

These are the windows published by the suppliers' own price data on 22 October 2026. Times are UK time. Prices vary a little by region and change when tariffs are repriced, so treat the pence as a guide and check your own bill or app.

Tariff	Cheap hours	Cheap rate (around)	Rest of the day (around)
Octopus Go	12:30am to 5:30am	9.4p	33p to 35p
EDF GoElectric	11pm to 6am	6.7p	31p to 35p
E.ON Next Drive	midnight to 6am	8.5p (6.5p on the smart charger version)	33p to 35p
Cosy Octopus	4am to 7am, 1pm to 4pm, 10pm to midnight	14p	28p, rising to about 43p from 4pm to 7pm
Agile Octopus	changes every half hour	often lowest overnight and some afternoons	highest from 4pm to 7pm
Economy 7	seven hours overnight, set by your meter	varies by supplier	varies by supplier

For comparison, the standard variable rate I checked in Yorkshire was about 25.6p a unit, all day, every day.

Notice what that table is really saying. Time-of-use tariffs aren't cheaper across the board. The cheap hours are much cheaper, and the rest of the day costs more than a standard tariff. They pay off when you can move a decent chunk of your use into the cheap window, and they cost you money when you can't.

Agile: the one that changes every day

Agile Octopus sets a new price for every half hour, based on the wholesale market. Tomorrow's prices are usually published in the afternoon, so by teatime you can see the whole of tomorrow.

Two patterns show up again and again:

• 4pm to 7pm is the expensive bit. That's when the country gets home, turns everything on and the grid is under the most pressure.
• The cheapest slots move around. Often overnight, sometimes the early afternoon, and on windy, sunny days prices can even drop below zero, which means you're paid to use power.

Because it moves, guessing doesn't work well on Agile. You either check the prices or let something check them for you.

Economy 7: check your meter, not the internet

Economy 7 gives you seven hours of cheaper electricity overnight, but the seven hours aren't the same for everyone. They're set by your meter and can differ between regions and even between houses on the same street. Some meters also don't change for British Summer Time, so the window shifts by an hour twice a year.

Your bill, your supplier's app or a quick call to your supplier will tell you your actual hours. Do that once, write it on the inside of a kitchen cupboard, and you're sorted.

What's worth moving into the cheap hours

The big wins are things that use a lot of power and don't care when they run:

• Electric car charging. By far the biggest load in most homes that have one, and the reason most of these tariffs exist.
• Immersion heater. A 3kW element heating a tank of water is a lot of units.
• Tumble dryer, washing machine and dishwasher. Less dramatic per run, but they add up over a year.
• Charging batteries: e-bikes, mobility scooters, power tools.

The small stuff isn't worth rearranging your life for. Boiling the kettle at midnight to save a fraction of a penny is a hobby, not a strategy.

A word on running appliances while you sleep

Here's the catch with "the cheapest time is 2am". Fire services advise against leaving washing machines, tumble dryers and dishwashers running overnight or while you're out, because if something goes wrong you have far less time to react. Devon and Somerset Fire and Rescue and London Fire Brigade have both said so publicly.

So be practical about it:

• On Cosy, the 10pm to midnight and 1pm to 4pm windows let you use cheap power while you're up.
• On Go, GoElectric and Next Drive, an early start works: put the dishwasher on as soon as you're up and the window's still open.
• On Agile, look for a cheap slot in the evening or at the weekend rather than defaulting to the middle of the night.
• Electric car chargers are designed to run unattended, which is exactly why EV tariffs put the cheap rate overnight.

Keep a working smoke alarm, clean the tumble dryer filter every load, and don't overload sockets. Boring advice, but it's the advice that matters.

The greener time is often the cheaper time

There's a happy overlap here. When there's lots of wind and solar on the grid, wholesale prices tend to fall, and so does the carbon behind each unit you use. National Grid publishes a forecast of this for each region. When I checked Yorkshire's forecast this week, the dirtiest half hour was nearly ten times worse than the cleanest. Shifting your washing doesn't just save money; it often means you're running it on cleaner power too.

How to check your own cheapest time

Doing this by hand means finding your tariff's prices, working out how long your appliance runs, and adding up the half hours. That's a lot of effort for a washing cycle.

That's why I built Cheap Watts. Pick your supplier and tariff, pick the appliance, and it tells you:

• the cheapest time to start it, and what it costs then compared with right now
• the greenest time, from National Grid's regional forecast
• what to set your delay timer to
• a calendar reminder, if you want one

It uses live prices for Octopus, EDF and E.ON Next, and you can type in your own hours and rates for Economy 7 or any other supplier. It's free, and there's no sign-up.

If you're on a standard tariff, it'll tell you honestly that the time doesn't matter. If you're wondering whether a time-of-use tariff would suit you better, the Should I switch? tool runs your own smart meter data against each tariff, standing charges included.

Start with one thing: find out which tariff you're actually on. Everything else follows from that.