ILR How is the journey calculated when crossing windows within 180 days of departure?

Q: How many statistical windows does an outbound trip cross, and where should the total number of days be placed? A: Calculate according to the overlapping parts of the dates. The contribution of the same trip in different windows can vary.

This article discusses the calculation of absences before applying for permanent residency, taking as an example a work visa holder subject to the rolling rule. The current Appendix Continuous Residence of the Immigration Rules, CR 3.1, states that usually, a person must not be absent for more than 180 days during any twelve-month period. Before calculating, it is necessary to determine one's qualifying period and applicable rules; when involving historical transitional arrangements or statutory allowable absences, separate verification is required.

My judgment is: when arranging the next trip using the calculation results, at least the start and end dates of the window and the number of days contributed by each trip should be visible. A single total figure is not enough to decide how long to stay.

A 60-day trip, possibly only 20 days are counted within the window.

When preparing the calculation, first record the departure date from the UK and the actual return date to the UK for each trip, then sort out the first and last days of the complete departure period in between. The window used for accounting must also specify clear start and end dates. Stack the two periods together, taking the later of the two start dates and the earlier of the two end dates, counting only the dates between the two, including both ends. If the start date is already later than the end date, the contribution of this trip to the window is zero. If a single trip passes through multiple countries without returning to the UK, the same absence period is still used; changes in destination do not add a new absence or interrupt the existing absence.

Write the above operation as a formula, applicable to the complete absence dates that have been sorted out:

The number of days within the window = the earlier end date - the later start date + 1; if the two date ranges do not overlap, it is recorded as 0.

Take a pure calculation example: A trip has 60 absence days that can be counted. The first 40 days fall before the checked window, and the remaining 20 days fall within the window. This window adds 20 days. When checking another window covering the entire trip, 60 days are added. For trips crossing windows, the intersection should be taken segment by segment, and the total number of days cannot be entirely attributed to one side of the departure day.

The same day can participate in multiple inspection windows, but only once in the same window.

Within each window, add up the contribution days of each trip, and compare with 180 days. When making the table manually, you can move the window by one day each time, check all twelve-month windows that need to be covered during the eligibility period, and keep the maximum value and its start and end dates. For trips that have not yet departed, save a separate forecast table and add the planned date; this will help clearly see which windows the new trip will affect, and the original travel records will also be convenient for further verification.

A few more days, go back along that line of inquiry

Assuming a window has already existed for 155 days, the new schedule will have 30 days falling within it, and the original absence has not been removed, resulting in 185 days. If old dates are removed after the window moves, the intersection needs to be recalculated.

This also explains why predictions cannot be based solely on the numbers on the expected return day: the peak might occur at some point during the journey. In practice, it is possible to retain the two maximum values of "historical records" and "after joining the plan", then check the few trips that contribute the most. If the two calculations differ by several days, check whether the original return date was used, whether the same trip was entered twice, and whether the window boundaries were overcounted or undercounted by one day. Keep the original dates, window distribution, and total separately. The difference can usually locate the specific line, without having to recheck all trips.

When the date is temporarily uncertain, I will estimate the new schedule based on the longer absence period, and update it once the evidence is verified; for formal declaration, the actual date with basis should still be filled in.

The "Continuous residence" guidance updated on June 8, 2026, section 6.2, also includes a detail directly related to verification: when the declared date is inconsistent with other records, the case officer must give the applicant an opportunity to explain the discrepancy and confirm the correct date. This requirement does not guarantee approval of the application, but it indicates that retaining supporting evidence for changes is useful: the old value, new value, reason for adjustment, and corresponding documentation should be consistent with each other.

[Data Source] Home Office "Immigration Rules" Appendix Continuous Residence; "Continuous Residence" Guidance sections 6.2, 6.5 and 6.8. This article is for reference only; please consult a licensed lawyer for specific issues.

1. Complete the missing intervals for each trip and mark the date evidence next to them.
2. Expand the window where the maximum value is located, check the overlapping days in each round, and then add the next schedule for recalculating.
3. Save the change and correction records and calculation version, and update the forecast table with the actual date after returning to the UK.

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