About KinLedger Tools

Who we are

KinLedger is an independent small shop that makes spreadsheets, in Excel and Google Sheets formats, for people who need to keep records: trips, dates and paperwork. KinLedger Tools is the free part of what we do: a few calculators you can use right here in your browser.

We are not a law firm, a tax adviser, a visa agency or a government body, and we are not connected to any of them.

How the calculators are made

AI tools help us build the spreadsheet files and this website. We choose what goes in, and we do not rely on the AI tools alone to get the numbers right:

Each rule is taken from a page of the government body that makes it: the European Commission for the Schengen 90/180 rule, USCIS for naturalization, and the IRS for the substantial presence test. The pages we read are linked on each tool page, with the date we checked them.
Every calculation is checked against the official worked examples where the authority publishes them: the two examples in the European Commission's manual, the early filing and travel examples in the USCIS Policy Manual, and the IRS example for the substantial presence test.
The code is also tested against a separate day-by-day count of every day, on hundreds of random cases, including the edge cases (the first and last day of a period, one day over a limit, stays that cross the new year).
Where we could not confirm a detail on an official page, the tool page says so instead of guessing.

What we cannot promise

Rules change, and a calculator cannot see your whole situation. The tools are helping tools, and only the authorities decide. Please read the disclaimer.

Found a mistake?

If a result looks wrong, or an official page has changed, please tell us. The simplest way is to send a message through our Etsy shop. Include the dates you typed and the result you expected, but please leave out any personal details such as your name or passport number.