A worked example: 8 pomodoros at the classic 25/5/15 pattern
Running the pomodoro timer's formula with 8 pomodoros, 25-minute work sessions, 5-minute short breaks, 15-minute long breaks, and a long break scheduled every 4th pomodoro produces a total work time of 200 minutes (8 × 25), a total break time of 45 minutes, 6 short breaks, and 1 long break. Work plus break comes to 245 minutes total, which the calculator formats as "4h 5m."
The formula: work time plus break time, with N-1 breaks
The calculator first works out how many breaks exist at all: with 8 pomodoros there are (8 − 1) = 7 breaks between sessions, since no break follows the final pomodoro. Of those 7, one lands on the 4th pomodoro and becomes a long break — floor(7 ÷ 4) = 1 — leaving 7 − 1 = 6 short breaks. Total work time is pomodoros × work minutes (8 × 25 = 200), total break time is (short breaks × short length) + (long breaks × long length) = (6 × 5) + (1 × 15) = 30 + 15 = 45, and the grand total is 200 + 45 = 245 minutes.
A longer deep-work variant: 12 pomodoros at 50/10/20
Switching to a deep-work pattern — 12 pomodoros of 50 minutes each, 10-minute short breaks, 20-minute long breaks, and a long break every 3rd pomodoro — changes every number. There are (12 − 1) = 11 breaks total; floor(11 ÷ 3) = 3 of them are long breaks, leaving 8 short breaks. Total work time is 12 × 50 = 600 minutes, total break time is (8 × 10) + (3 × 20) = 80 + 60 = 140 minutes, and the session runs 600 + 140 = 740 minutes — formatted as "12h 20m."
Why the last pomodoro never gets a break
The N-1 rule matters more than it looks: a 6-pomodoro session at the same 25/5/15 pattern produces (6 − 1) = 5 breaks, of which floor(5 ÷ 4) = 1 is long and 4 are short, for a total break time of (4 × 5) + (1 × 15) = 35 minutes on top of 150 minutes of work — 185 minutes, or "3h 5m." Doubling the pomodoro count doesn't double the break time in a simple way, because the long-break cadence resets the ratio of long to short breaks each time the count crosses another multiple of the long-break interval.