time-compute

Seven services on https://fittings.sh for the arithmetic models are worst at and most confident about: what day a thing lands on, what time that is somewhere else, and whether the clocks moved in between. None of it is hard, which is exactly why it gets done from memory and comes back wrong. A date is either right or it is a missed deadline, and nothing in the wrong answer looks wrong.

Live catalog for this slice: https://fittings.sh/catalog?category=Deterministic%20compute — these seven are the calendar and clock part of that category. Browsing it, searching it and reading any schema cost nothing.

When to reach for this

When a date you are about to state will be acted on: a deadline, a delivery, a cut-off, a settlement, a notice period, a renewal. When the answer depends on which days are working days somewhere, and you do not hold that country's holiday list. When two people in two zones have to be in the same meeting. And whenever a conversion crosses a date on which the clocks change, because that is where an offset recalled from training data stops being right.