How the math works
A billing increment is the smallest block of time you bill. If your increment is 15 minutes, a 5-minute call bills as 15. A per-call minimum goes further: it sets a floor for the whole call, so a quick check-in still reflects the context-switch, the prep, and the follow-up that a real call always carries.
This calculator applies your minimum first, then rounds to your nearest increment, and never lets a real call fall below one full unit. That is the same order Paidwell applies automatically the moment you log a call, except Paidwell also adds prep and post padding if you set it.
Why the gap is bigger than it looks
The leak is not one call. It is every short call, every month, compounding across a year. A dozen 20-minute calls billed as 20 minutes instead of an hour, at a senior rate, is the difference between a rounding error and a real number. The calculator shows the annual figure because that is the one that changes behavior.