Schengen calculators: what a 90/180 calculator needs to do

A Schengen calculator adds up the days you have spent in the Schengen area and checks them against the 90/180 rule. The European Commission publishes a free one that tells you whether a stay is within the limit and how long you could stay from a given date, based on the trips before it. If you also have later trips booked, you need a calculator that counts past and future trips together, because a trip now can use days a later trip depends on.

What does a Schengen calculator have to do?

The rule allows 90 days in any 180-day period, and the 180 days are counted back from each day of your stay. So a calculator cannot do one sum. It has to:

• count the day of entry and the day of exit as full days
• treat all 29 Schengen countries as one total
• repeat the count for every single day of a stay, each with its own 180-day window
• let old days drop out of the window as time passes, including part-way through a stay

A spreadsheet that subtracts your days from 90 gets the first two right and the last two wrong. The 90/180 rule explained has worked examples of where that goes wrong.

How does the EU's short-stay calculator work?

The Commission's calculator is on its short-stay calculator page. You type in the entry and exit dates of your previous stays and choose one of two modes. The Commission describes them like this:

• Check mode (labelled "Control" in the tool) "calculates the length of previous and/or on-going stays to check if the stay complies with the 90/180-day rule (on the day of the check)".
• Planning mode "calculates the maximum length of stay allowed on a particular day in the future".

It is the Commission's own implementation of the rule, it is free, and it was built for border guards as well as the public. The Commission is clear about its status: "The calculator is a helping tool only; it does not constitute a right to stay for a period resulting from its calculation."

Since 10 April 2026 there is also an official tool that reads your own record in the Entry/Exit System and tells you how many days remain, for a date you give it.

What do the official tools not do?

Both official tools answer one question at a time: given the stays before this date, how long can I stay from this date? The Commission's manual says planning mode works "on the basis of previous entry and exit dates".

Neither works backwards from a trip you have booked for later. They also do not keep your trips, so you re-enter them each time, and the Commission's manual says its calculator "cannot take into account" the bilateral agreements that give some nationalities extra time in certain countries.

Why do future trips matter?

Because the answer to "how long can I stay in February?" depends on what you have booked for May.

Take a traveller who spent 10 October to 8 November 2026 in Italy (30 days) and has booked 1 May to 29 June 2027 in Greece (60 days). They want to know how long they can go for from 1 February 2027.

• Looking only backwards, the answer is 60 days, until 1 April. There are 30 days in the window and 90 minus 30 is 60.
• Counting the Greek trip as well, the answer is 30 days, until 2 March.

Both answers are correct for the question asked. But if they stay the 60 days, the Greek trip no longer fits: by the end of June the window would hold 60 days from February and March plus 60 in Greece. To keep the booked trip, February has to stop at 30 days.

A backward-looking calculator will show this only if you think to re-run it for the last day of the later trip with the new stay typed in. A planning calculator does that check for every date automatically.

Which kind of calculator do I need?

The EU's calculator is enough if you make one or two trips a year, they are well spaced, and you want to check a single stay.

You need one that handles future trips if you:

• book trips months ahead and add others in between
• spend close to 90 days in most 180-day periods, as many second-home owners and long-stay travellers do
• travel with other people whose trips differ from yours
• want to see the answer for every date at once, not test dates one by one

How Schengen Simple helps

Schengen Simple is a calculator of the second kind. You enter your trips once, past and planned, and it keeps them. The calendar then shows, for every date, how long you could stay if you arrived that day, with your later trips already taken into account, and it warns you if a change would push any trip over the limit. It is a planning tool: like the EU's calculator, it does not give you a right to stay, and the decision at the border is the officer's.