Time slot generator — split a day into appointment slots

How to use the time slot generator

1. Set Day starts and Day ends.
2. Enter the Slot length in minutes (at least 5) and a Gap between slots if you need time to reset between appointments.
3. Enter Break starts (optional) and Break length for lunch or a team meeting. A length of 0 means no break.
4. Choose the Format: 24-hour (14:30) or 12-hour (2:30 pm).
5. Read the Slots count and Bookable time, then copy the list, download it as .txt, or download the Booking sheet as time-slots.csv.

What it does and when to use it

Working out appointment times by hand goes wrong quickly once gaps and a lunch break are involved. This tool does the arithmetic for parent–teacher evenings, interview days, clinic bookings, office hours and tutoring sessions. Paste the list into a booking form, or print the CSV as a sign-up sheet.

Once the slots are fixed, send each confirmed booking as a calendar invite with the iCal event generator. The weekly planner gives you a whole week to fill in, and the meeting cost calculator shows what a long interview day costs in staff time.

How it works

Times are turned into minutes after midnight. Starting at the day’s start, the tool checks whether a slot of the chosen length would overlap the break. If it would, the next start jumps to the end of the break. If not, the slot is added and the next start moves forward by the slot length plus the gap. This repeats until the next slot would end after the day ends.

Bookable time = number of slots × slot length ÷ 60, shown in hours.

Worked examples

A standard day (the preset). 09:00 to 17:00, 30-minute slots, no gap, a 60-minute break at 13:00 gives Slots: 14 and Bookable time: 7 h. The morning runs from 09:00 – 09:30 to 12:30 – 13:00, and the afternoon starts with 14:00 – 14:30.

Interviews with time to write notes. Same day, 45-minute slots with 15-minute gaps, no break, 12-hour format: Slots: 8, Bookable time: 6 h, starting 9:00 am – 9:45 am and ending 4:00 pm – 4:45 pm.

Short sessions around a mid-morning break. 08:30 to 12:00, 20-minute slots, 5-minute gaps, a 15-minute break at 10:15:

08:30 – 08:50
08:55 – 09:15
09:20 – 09:40
09:45 – 10:05
10:30 – 10:50
10:55 – 11:15
11:20 – 11:40

The slot that would start at 10:10 overlaps the break, so the next one starts at 10:30. That gives 7 slots, or 2.33 hours of bookable time.

Limits and tips

• If the day is shorter than one slot, you see “No slot of that length fits in the day.”
• Only one break per day is supported. For two breaks, run the tool once for the morning and once for the afternoon.
• Leftover minutes at the end of the day are not used. If the day ends at 17:00 and the last slot ends at 16:45, those 15 minutes stay free.