The cheapest time for electricity: find the day’s cheapest window
The cheapest moment is not always the cheapest window. It depends on how long the appliance runs.
Checked by Radif Partners · Editorial policy · Method and sources
Since 1 October 2025 Swedish electricity has been priced per quarter hour, and the day’s 96 prices are set in the auction at 12:00 the day before. So the cheapest time to run an appliance is not a fixed clock time that holds every day, but something you work out from tomorrow’s list. The key is to look for the cheapest continuous window as long as the appliance needs, not just the cheapest quarter. In an invented example with 24 hourly prices, the cheapest hour is at 13:00, but the cheapest six-hour window starts at 10:00. The calculator runs the same search on the prices you paste and turns them into all-in prices with your grid and tax. It only pays on a quarter-hour contract; on a variable or fixed price, timing does not change the bill.
What is choosing the cheapest time every day worth?
Value per year, with VAT
SEK 1,369
| Gap per kWh with VAT | 75.0 öre/kWh |
| Per day | SEK 3.75 |
| Per month | SEK 114 |
Spot prices before VAT that you enter. Only applies on a quarter-hour contract.
How the search for the cheapest window works
Picture a window as long as the programme. The calculator places it on the day’s first quarter, works out the average price, moves it on by one quarter and repeats, until it has tried every position. The position with the lowest average is the cheapest start time. The method accounts for a long charge having to pay for the dearer quarters at its start or end too.
| Length | Cheapest start | Average in the window | All-in incl. VAT |
|---|---|---|---|
| 1 hour | 13:00 | 28.0 öre/kWh | 111.3 öre/kWh |
| 3 hours | 12:00 | 31.0 öre/kWh | 115.0 öre/kWh |
| 6 hours | 10:00 | 44.7 öre/kWh | 132.1 öre/kWh |
The example shows how the choice changes with length, and why looking at the day’s lowest price in the app is not enough. For a short dishwasher run the single cheapest hour fits. For a long charge another part of the day gives the lowest average, because the cheapest hour is surrounded by dear ones.
Quarters, hours and clock-change days
Paste 96 prices and the calculator works in quarters; paste 24 and it works in hours. Both work, but quarters give a sharper picture: a window can start and end mid-hour, and the cheapest slot for a two-and-a-half-hour dishwasher run is found more precisely. On the days the clocks change to summer or winter time, the day has 92 or 100 quarters. The calculator then uses the number of prices you pasted and shows times from midnight, so double-check the start time on those days.
If you only have part of the day, say the evening and night prices, that works too: the calculator searches the list you gave it. A window cannot be longer than the list, so an eight-hour charge needs at least eight hours of prices.
From start time to timer
Dishwashers, washing machines and wallboxes often offer a start time or a delayed start. With a start time you set the clock time the calculator suggests. With a delayed start you count the hours from now until then. Some machines set when the programme should finish rather than start; subtract the programme length. For an electric car, charging can often be controlled in the car’s or the wallbox’s app, where you set a start or end time.
Where the prices come from
Tomorrow’s prices are known after the day-ahead auction, which Svenska kraftnät describes: buy and sell bids for each quarter hour are matched at 12:00 the day before. The exact time lists appear in apps varies, so count on the afternoon. We show no spot prices ourselves, since they may not be freely republished; get them from your retailer or the ENTSO-E transparency platform.
From spot price to all-in price
The gap between two windows is only the spot gap, plus VAT. Energy tax of 36.0 öre/kWh and the grid transfer fee are the same around the clock unless your grid has peak and off-peak rates. That is why percentage gaps look smaller in all-in prices than on the exchange board. The calculator shows both: the curve you see is the all-in price per period, on your grid.
Three traps to avoid
- The wrong contract. On a variable monthly or fixed price you pay the same per kWh whenever you use power, so shifting gains nothing on your bill. See quarter-hour prices.
- Everything at once. If your grid has a power charge, starting charging, dishes and laundry in the same cheap window can cost you. Spread them out.
- The wrong zone. The prices you paste must be for your bidding zone. Check the app shows the right one.
What it is worth in kronor
The value depends on how many kilowatt-hours you can move and how wide the gap is. A 1 kWh dishwasher run moved to a window 60 öre cheaper saves 75 öre with VAT. A 30 kWh charge with the same gap saves SEK 22.50. The mini-calculator above works from your own daily use; the charging calculator and the dishwasher calculator show the cheapest start directly once you paste the prices.