Count a moving window, not two halves of a year
The Commission’s calculator instructions explain the rolling calculation: include both arrival and departure dates and look back over 180 days. A trip crossing New Year does not receive a new allowance on 1 January.
Start with a list of actual entry and exit dates. Keep planned trips separate from completed travel so that a cancelled booking does not accidentally become a day of presence. Use the 90/180 calculator to check each proposed stay, not just the position on its first day.
A worked example
Suppose you enter on 1 January 2026 and leave on 31 March 2026. That is 90 days: 31 in January, 28 in February and 31 in March. If these are your only counted visits, 1 April cannot be added as another short-stay day. After 90 full days outside, 30 June can begin a new 90-day run: earlier days fall out as new days are added.
That example depends on its exact dates. Do not reuse its answer for scattered trips or a leap year.
The calculator is only one check
Read your visa’s validity dates, entry allowance and authorised stay as well. A calculation showing spare days does not override a shorter visa. The official sticker guide explains the separate fields.
Days authorised under a Schengen country’s own residence permit or long-stay visa are treated differently from ordinary short stays. Do not remove every European trip merely because you possess a residence card; travel to other countries needs separate assessment.
If records disagree
Compare passport records, tickets and your actual movements. Ask the relevant border authority about an incorrect official record. Do not choose whichever count produces the most remaining days.
Leave a travel buffer where possible. An overnight disruption near your limit is harder to manage than a trip planned comfortably within it.