ABOUT

Puerto Rico’s Act 60 decree drops tax on capital gains to zero for bona fide residents. Bona fide has a definition, and it is a presence test: 183 days on the island, every tax year. That number is where the app gets its name.

Take it out of the calendar and 182 days are left to spend anywhere else. Go one day over and the island only gets 182, the test fails, and a year that was going to be tax-free is not. It is the same number read from either end, which is the whole design problem.

One83 counts the days away. Home carries the number still free and the trips already promised to a flight, with a single row saying whether the year still passes. The calendar leaves island days unmarked, because there is nothing to decide about them, and puts a chip only on the days away: filled if the trip happened, dotted if it is still a plan. The planner prices a trip before anyone commits to it. Leaving August 22 and coming back August 29 costs 6 days, and the year drops from 182 to 176.