Entry and exit days

Schengen's own rule says so

The date of entry is the first day of stay and the date of exit is the last.

A same-day visit counts as one day.

The official rules don't all count days the same way. For Schengen, the day you arrive and the day you leave both count as full days (Schengen Borders Code, Article 6(2)). BorderRunner uses that same rule for every clock, its tax clocks included. The official tax tests work differently:

US Substantial Presence Test

Any part of a day in the US counts.

FEIE physical presence test

Only full days, midnight to midnight, in foreign countries count. BorderRunner counts your days in the US instead, so the day an overnight flight lands abroad counts as foreign in the app but not for the IRS; keep a few days' margin.

UK tax residence

A day counts only if you're in the UK at midnight. BorderRunner counts more simply: every day you're in the UK, the day you leave included, in the calendar year rather than the UK tax year that starts on 6 April.

So the same trip can be 10 days under one official rule and 8 under another. BorderRunner counts it as 10 on every clock.

If you leave one country and enter another on the same day, both count that day.

Arrive on the 29th, 30th or 31st and the month 6 months later is shorter? We use the last day of that shorter month, minus one, to keep you safe. For example, arrive 31 Aug and the app says leave by 27 Feb.