Class Schedule Conflict Detector
Check a class schedule for conflicts: enter each section's days (Mon to Sun) and start and end times to list every overlap by day and the free gaps. How it works
Use the Class Schedule Conflict Detector
About the Class Schedule Conflict Detector
Two class sections conflict when they meet on the same day and each starts before the other ends; every shared day counts as one conflict. The sample schedule (Math 101 MWF 9:00 to 9:50, History 201 MW 10:00 to 10:50, Physics 101 TTh 13:00 to 14:15, English 110 MWF 11:00 to 11:50) has 0 conflicts. Add a chemistry section on MWF from 9:30 to 10:20 and the class schedule conflict checker reports 5: three days against Math 101 and two against History 201.
Free gaps in the sample schedule
| Day | From | To | Minutes |
|---|---|---|---|
| Mon | 09:50 | 10:00 | 10 |
| Mon | 10:50 | 11:00 | 10 |
| Wed | 09:50 | 10:00 | 10 |
| Wed | 10:50 | 11:00 | 10 |
| Fri | 09:50 | 11:00 | 70 |
What Show Gaps lists for the four sample sections. Tuesday and Thursday have one class each, so they have no gap. The tool shows 70 minutes as 1h 10m.
How the checker counts clashes
| Schedule | Conflicts | Gaps listed |
|---|---|---|
| The sample schedule | 0 | 5 |
| Sample plus a chemistry section MWF 9:30 to 10:20 | 5 | 3 |
| Mon 9:00 to 9:50, then Mon 9:50 to 10:40 | 0 | 0 |
| Tue lab 9:00 to 12:00, a seminar 9:30 to 10:00 inside it, then a class 13:00 to 14:00 | 1 | 1 |
Back-to-back classes do not conflict and leave no gap. A class nested inside a longer one is one conflict and opens no gap; the only gap in the last row is 12:00 to 13:00.
How to use this tool
- Type a name for each section, tap the days it meets (Mon to Sun) and set its start and end time. Add Section adds another.
- Read the conflict count: each clashing pair is listed with the day and both time ranges, and the clashing sections get a red border.
- Press Show Gaps to list the free time between classes on each day. It works with conflicts present: overlapping sections simply leave no gap between them.
Frequently asked questions
- How do I check if two classes overlap?
- They overlap when they share a day and start A is before end B and start B is before end A. Math 101 at 9:00 to 9:50 and a chemistry section at 9:30 to 10:20 overlap by 20 minutes on every day they share.
- Why does one clash count as three conflicts?
- Each shared day is counted on its own. Two sections that both meet Monday, Wednesday and Friday at overlapping times are three conflicts, and the list names each day, so you can see which meetings clash.
- Do back-to-back classes conflict?
- No. A class ending at 9:50 and another starting at 9:50 do not overlap, and no gap is listed between them. The checker adds no travel time, so allow for walking between buildings yourself.
- What if one class sits inside a longer one?
- It is one conflict on that day, and no free gap is listed inside the longer class. A gap opens only after every earlier class that day has ended: a lab from 9:00 to 12:00 with a seminar from 9:30 to 10:00 inside it, then a class at 13:00, gives 1 conflict and one 60-minute gap from 12:00.
- What happens if a class ends before it starts?
- The section shows "End time must be after the start time" and is left out of the check until you fix it. A section is also skipped until it has a name and at least one day.
- Can it check weekend or evening classes?
- Yes. Any day from Monday to Sunday can be picked, and the start and end are any time of day, so a Saturday lab or a 19:00 seminar is checked like the rest.
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