Best residency tracking apps for state and country day counts

Good for: anyone who splits the year between countries, between US states or both and wants every count worked out from the same record of where they were each day. If you start tracking mid-year, Geostay rebuilds past trips from the date and place stored with your photos, or from a Google Maps Timeline export, a Flighty export or a CSV file.

In Geostay, you add a counter for each country or state you need, choosing from the tax residency day tests of 184 countries, 27 US states and New York City. A Spain counter, for example, counts your days in the calendar year and shows how close you are to Spain's limit, which you cross after 183 days. Every counter follows the rule of its country or state, down to whether the day you arrive or leave counts.

What it offers: Geostay shows each test with its legal source and the date it was checked. For the UK Statutory Residence Test, it counts days you are in the UK at midnight, by tax year from 6 April. For the US Substantial Presence Test, it adds this year's days, a third of last year's and a sixth of the days of the year before. It records the country your iPhone is in each day, even when the app is closed. Because it works out the country from a map stored in the app, roaming and flight mode leave no gap. On days in the US, it also records which state you are in. Its counters for New York, Connecticut, Pennsylvania, Rhode Island and Minnesota do not count a day when you only pass through the state. Tapping Create a report makes a PDF of your day counts and your stays for the period you choose, plus a CSV day log with the date, country, state and city of each day. Any boarding pass or ticket you attached is included. Your travel history, photos and documents stay on your iPhone, and your locations are not sent to a server or a mapping service.

Consider: Geostay needs no account, so you move your record to a new iPhone by restoring a backup.

Good for: snowbirds, remote workers and frequent travelers who count days by country, US state or Canadian province and want planned trips shown in projected day counts.

TaxBird uses your phone's location in the background to record where you spend your time, and shows how many days you have spent in each place and how many remain before a residency limit.

What it offers: TaxBird counts your days in any country, each US state and Canadian province, and New York City. At the end of the year, it makes a report of your residency days to share with your accountant.

Consider: The CSV you can request from TaxBird is a yearly summary.

Good for: multi-state residents, executives who travel a lot for work, professional athletes and anyone who has to split income by the days worked in each state.

TaxDay tracks your travel in the background with your phone's GPS, checks it against the residency tax rules of every US state, and keeps a log of your taxable days in each state for your tax professional.

What it offers: TaxDay tracks your days in New York City as well as in each state. It also separates work days from non-work days, so you can allocate income state by state. You can attach receipts to your trips and export a report to share with your accountant.

Consider: Your data is kept in TaxDay's cloud storage, and you can reach it through a web portal.

Good for: people who live in more than one state or move between countries for work, especially anyone proving a change of domicile who wants records an auditor can verify.

Domicile365 counts your days by country, state, city, province and territory, checks them against tests such as the UK Statutory Residence Test, and lets your CPA see the counts through a read-only advisor portal.

What it offers: Domicile365 records your days automatically and counts them by city as well, New York City included. It has separate checks for Schengen, the US Substantial Presence Test, a rolling 183-of-365-day count, Puerto Rico and the UK Statutory Residence Test on the UK tax year from 6 April. It exports CSV logs and signed PDF audit logs, which can be checked on Domicile365.com to confirm the location records were not altered. Besides iOS, it runs on macOS, Android and Windows, and you can check your day counts on the website too.

Consider: Location is recorded continuously and saved in the cloud.

Good for: expats, digital nomads and dual residents who want multi-year tests, and flight crew who need work travel left out of their counts.

Flamingo Compliance records your location automatically and builds a travel timeline of the countries, US states and cities you visited, with customizable trackers for tax residency, domicile and visa day counts.

What it offers: Flamingo Compliance lets you set up single-year or multi-year trackers across 200+ countries, all 50 US states and New York City, for tests such as the UK Statutory Residence Test and the US presence tests. Crew Exemption Mode leaves flight crew work travel out of tax residency and permanent residency calculations. The app can also rebuild your travel history by scanning your Photo Library. It exports a customizable CSV report of every tracker. There is no account or registration, and your data is stored on your device and in iCloud.

Consider: It never tracks your precise location and works out your general location at city level.

Good for: snowbirds, second-home owners, green card holders and frequent travelers who also track visa limits and want to see their counts on a computer as well as the phone.

iReside uses GPS to count every day you spend in each US state and country, and checks those days against the 183-day rule, state residency tests and the US Substantial Presence Test.

What it offers: iReside counts NYC separately from New York State. It has the IRS's weighted three-year formula for the US Substantial Presence Test built in. It also comes with 40+ ready-made trackers, among them ESTA, Thailand, Green Card, UK ILR and UAE residence. Its PDF and CSV reports cover your day counts, residency status and full timeline. You can view all your iReside data from any browser, without your phone.

Consider: Your timeline is tied to your iReside account, which is how you recover it on a new phone.