About DayCount EU

A calm, precise way to keep track of your Schengen days and tax days, without handing your travel history to anyone.

The Entry/Exit System means the border now counts your days from biometric records. Travellers still need to understand their own count, plan trips and prove when they left. DayCount EU does those three things on your phone.

Methodology

Dates are plain calendar dates

Every date is a day, never a timestamp. This avoids the off-by-one errors that time zones and daylight-saving changes cause.

The Schengen rule

A day counts if you are in the Schengen area for any part of it, so entry and exit days both count. For a given day the window is that day and the 179 days before it, and the count must be 90 or fewer on every day you are present. This is the method in the European Commission's calculator manual.

Commitments-aware planning

For a planned entry date, the engine finds the longest stay that keeps every present day compliant, including every day of trips you have already committed to or planned, not just the new stay.

Strict and family-adjusted counts

The engine returns a strict count and a family-adjusted count for periods you mark as travelling with or joining an EU-citizen family member. The strict count is always the primary figure.

Tax conventions

Each jurisdiction states how it counts days: any part of a day, the UK midnight rule, Spain's physical days plus a risk count for sporadic absences, Portugal's best 12-month window, and the US substantial presence formula. Rules we could not confirm against an official source are marked approximate.

How it is tested

• Golden vectors. The worked examples in the Commission's manual (for example 16 days used on 15 June 2014, 90 on 29 August, and 20, 20, 50 and 90 days for the entry dates in the second example) are test cases.
• An independent reference. A deliberately simple implementation written straight from the rule text is compared with the optimised engine on tens of thousands of randomised cases, for day counts, breach detection, latest exit and maximum stay.
• Edge cases. Same-day trips, leap years, year boundaries, overlapping trips, open-ended stays, and the 90th day versus the 91st.
• One engine everywhere. The website's calculators and the app use the same engine, and a shared set of test vectors is run through the engine, the web calculator and the app so their results stay identical.

Where the rules come from

Jurisdiction parameters, the list of Schengen states and the ETIAS status are published as a versioned rules file. The app bundles a copy and checks for updates, so a policy change does not need an app release. Each tax rule lists its sources and whether it has been verified. Sources include the official EES page, GOV.UK, the Spanish tax agency and the OECD. Content last reviewed 28 Oct 2026.

Limits

Planning aid, not legal or tax advice. Border authorities' records are authoritative. DayCount EU is independent and is not affiliated with the European Union or any government. Tax results are indicators, not determinations.

Questions or corrections: see contact.