WhenMathMulti-Interval Time Total
Add up several time periods in a day. Choose "Sum" to total every interval as entered (overlaps counted twice), or "Unique" to merge overlapping and touching intervals first so shared time is only counted once.
Worked example
Two work sessions run 09:00-12:00 and 13:00-17:30. Neither overlaps, so both the sum and unique totals agree: 3h plus 4h30m is 7h30m. Now add a third session, 11:00-13:00, which overlaps the first by an hour and touches the second at 13:00. Sum mode adds all three durations regardless of overlap (3h + 4h30m + 2h = 9h30m). Unique mode merges the overlapping and touching intervals into one continuous 09:00-17:30 span first, giving 8h30m, the real amount of distinct time covered.
Common mistakes
- Using Sum mode when the real question is "how much distinct time was covered," which double-counts any overlap.
- Forgetting to confirm next-day for an interval that crosses midnight.
Limitations
This is clock-only arithmetic; it does not know about breaks, pay rates, or scheduling policy.
Frequently asked questions
- What counts as "touching" for merging in Unique mode?
- Two intervals that share an endpoint, such as 09:00-10:00 and 10:00-11:00, are merged into one continuous span in Unique mode.
- How many intervals can I add?
- Add as many as you need; each is validated independently.