Residency days you can show your accountant.
Dayproven is an iPhone app that records which US state or country you are in each day, on the phone, and counts those days under each test's own rule. It is coming to the App Store.
Each test's own rule
Any part of a day for New York and the US substantial presence test, midnight for the UK statutory residence test, entry and exit days for Schengen, full days for the 330-day physical presence test.
Every day shows its source
The location readings, the stays you entered and any change you made, for every day counted.
Gaps are shown, never guessed
When the record cannot say where you were, the day is counted as unresolved and waits for your answer. Each count says how many unresolved days could still be added to it.
Stays on your iPhone
No account and no server. Places are worked out on the phone from maps built into the app, so your locations are never sent anywhere.
The tests Dayproven counts
| Test | What counts as a day | Window |
|---|---|---|
| US state residency (New York, Connecticut, New Jersey, Massachusetts, Maryland, Minnesota, Delaware, Colorado, California) | Days present; for New York, "any part of a day". Where a statute does not define a day, Dayproven counts any part of a day and says so | The tax year |
| US substantial presence test | Any part of a day in the US | This year, plus a third of last year's days and a sixth of the year before |
| UK statutory residence test | In the UK at midnight, plus days added by the deeming rule when it applies | The UK tax year, 6 April to 5 April |
| Schengen 90/180 | Any day in the area, entry and exit days included | Any 180-day period |
| Physical presence test (foreign earned income exclusion) | Full days in foreign countries | Any 12 consecutive months |
Virginia and the District of Columbia are shown as days present, for reference only: their tests count days a place of abode was kept, which a phone cannot know.
Guides
Substantial presence test
How the IRS counts your US days over three years, with its worked example.
Statutory residence test
How UK days are counted: the midnight rule, transit days, exceptional circumstances and the deeming rule.
Physical presence test
How the 330 full days abroad are counted for the foreign earned income exclusion.
Counts, not advice
Dayproven counts days and shows the thresholds its sources set. It does not say whether you are resident anywhere or owe tax, and it is not tax or legal advice. Each rule in the app cites its primary source.