01
Enter car and charging details
Battery capacity, current SOC, target SOC, charger power, and departure time.
Tell us your battery size, how full it is now, how full you want it, your charger speed, and when you need to leave. That's all we need.
How it works
Smart charging starts with knowing the price.
ChargeWindow reads Danish hourly spot prices and works out the cheapest window to charge your EV — before you leave in the morning.
Three steps to a cheaper charge
02
We fetch hourly prices
ChargeWindow reads Danish spot prices and converts DKK/MWh to DKK/kWh.
We pull fresh hourly spot prices for West or East Denmark directly from Energi Data Service and add grid tariff, electricity tax, and VAT so you see the real price.
03
You get the cheapest charging plan
The plan highlights selected hours, expected cost, savings, and charging duration.
We pick the cheapest hours (or a clean block, if that's easier for your charger timer) and show you the expected cost, savings, and exact schedule.
Under the hood
How the numbers are made
Energi Data Service
Official Danish spot prices, updated hourly from the TSO. No third-party mark-up.
Cheapest-hours algorithm
Ranks each hour by all-in cost, picks the minimum set needed to deliver the requested energy, and trims the last hour to the exact kWh required.
Tariff & tax model
Grid tariff (Radius/Cerius zones), electricity tax (0.761 DKK/kWh), and 25 % VAT are layered on top of the raw spot price.
Live data
Prices refresh automatically. A built-in circuit breaker retries on transient EDS errors so stale prices never silently sneak in.
Frequently asked questions
Do I need an account?
No — the calculator works without signing in. An account lets you save your car profile so you don't have to re-enter details each time.
Which price areas are supported?
West Denmark (DK1, west of the Great Belt) and East Denmark (DK2, east including Copenhagen). If you're not sure which area you're in, your electricity bill will say.
How accurate is the cost estimate?
Spot price + standard tariff + electricity tax + VAT. It's a good estimate, but your actual bill also depends on your supplier's subscription fee and any flex-tariff discounts.
Will ChargeWindow start my car automatically?
Not yet — the Tesla integration is on the roadmap. Right now you copy the start time into your car's departure timer.
Ready to try it?
Enter your car details and we'll find the cheapest hours before your next departure.
Calculate cheapest charge