Most bookkeeping tools group a quarterly sales tax return by calendar quarter. Two states do not work that way, going by search excerpts of their instructions (not the full forms, so check your own notice):
- New York quarters run December-February, March-May, June-August and September-November, each due on the 20th of the month after.
- Pennsylvania semiannual filers cover February-July and August-January, due August 20 and February 20.
Until now the ai-bookkeeper sales tax worksheet grouped New York sales into calendar quarters and printed a warning. It now models both. A period that does not end in a calendar-aligned month is labelled by the month it ends in (2026-05), so --state NY and --freq semiannual --state PA work, and --end-month N sets the month the year's first period ends in for any other schedule.
The one trap was matching bank payments to periods. The rule is the period before the one the payment falls in. A first attempt that stepped back one month passed for March but charged a May payment to the period it was already inside; the existing test for calendar quarters caught it, and the final code steps back one whole period.
The worksheet is still a check to compare a return against, not a filing.