Event-duration planner
Add up an event's total running time from its planned activities and the buffers between them — or work out how many activities fit into the time you have.
Result
Total event length
Total event length
Result
Activities that fit
Minutes used
Minutes spare
How to use this tool
- Enter the number of planned activities (speeches, performances, agenda items).
- Enter the average length of each.
- Set a buffer between activities for transitions.
- Read the total event length.
Assumptions
- Assumes all activities are a similar length — for very different activity lengths, add them up individually instead for a more precise total.
Technical details: what the fields mean
- Number of activities
numberOfActivities - Number of distinct activities or agenda items planned.
- Average minutes per activity
minutesPerActivity - Average length of each activity.
- Buffer between activities
bufferMinutes - Transition time between activities — for seating changes, setup or applause.
Methodology
Total time = (activities × average length) + (buffer × number of gaps between activities).
Worked example
6 activities, 15 minutes each, 10-minute buffer
Inputs: Number of activities: 6, Average minutes per activity: 15 minutes, Buffer between activities: 10 minutes
Result: 2.33 hours (140 minutes)
A conference afternoon: 4 talks of 45 minutes with 10-minute changeovers
Inputs: Number of activities: 4, Average minutes per activity: 45 minutes, Buffer between activities: 10 minutes
Result: 3.5 hours (210 minutes) — a 13:30 start finishes at 17:00, before any break.
How many fit? 3 hours for 20-minute talks with 5-minute changeovers
Inputs: Time available: 180 minutes, Average minutes per activity: 20 minutes, Buffer between activities: 5 minutes
Result: 7 talks, using 170 minutes and leaving 10 spare. An 8th would need 195.
Practical guidance
- Always build in some contingency time beyond this calculation — events routinely run over their planned schedule.
- Add breaks and meals as their own activities rather than stretching the buffer, so the schedule shows them.
- Treat the minutes-spare figure as slack for late starts rather than squeezing in one more item.
Common mistakes
- Forgetting buffer time between activities entirely, which routinely makes real events run over their planned schedule.
FAQs
How do I include time between activities?
Enter the buffer you want for each gap. The calculator adds one buffer between each pair of activities, with no buffer after the last activity.
How many sessions fit in my slot?
Switch to the 'how many fit?' direction and enter the time available, the session length and the changeover. It returns the most that fit and the minutes left over.
Last reviewed: 2026-10-11
Assumes uniform activity lengths and a fixed buffer — real events often have some activities that run over.
This tool provides an indicative estimate, based on the assumptions stated above.
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