You submit at 12:04am. Canvas puts a red LATE label on it and tells you nothing else. Whether that costs you nothing, ten per cent, or the entire assignment depends on a setting you have probably never seen.
The label is not the penalty
This is the part that catches people. Canvas marks a submission late whenever it arrives after the due date, and that label appears whether or not any penalty exists. It is a timestamp, not a deduction.
The deduction, if there is one, comes from a separate late policy the instructor configures per course. There are three possibilities:
| No policy set | Nothing is deducted automatically. The label is informational and the instructor decides by hand — or ignores it. |
| Percentage per interval | A fixed percentage comes off per hour or per day late, usually with a floor below which it will not drop. |
| Missing submission policy | Anything never submitted is auto-scored, commonly at zero, once the deadline passes. |
How to find your course’s actual rule
Canvas does not show students the late policy anywhere obvious, which is most of why this is confusing. Three places to look, in order of reliability:
The syllabus. Almost every instructor who sets a penalty writes it there. Search the page for “late”.
A past submission. If you have handed anything in late before, open it in Grades. Canvas shows the deduction as a separate line from the score, so you can read the rule off it directly.
Ask. A one-line email gets an answer in a day and removes the guesswork for the whole term. Instructors are markedly more receptive to this question a week before a deadline than an hour after one.
The floor is the number that matters
Most percentage policies include a lowest possible score — often 50% or 60%. Once you are past the point where the deduction has bottomed out, being later costs nothing more.
That changes the decision. If you are already three days late on a capped assignment and something else is due tomorrow, finishing the new thing on time is worth more than rushing the old one, because the old one cannot get any worse. This is a genuinely useful thing to know and almost nobody knows it.
What to do in the hour before a deadline
Submit something. A partial submission on time, with the rest to follow, is nearly always worth more than a complete one late — especially where a missing-submission policy would otherwise score it zero. Canvas keeps every attempt, so resubmitting later does not destroy the first.
Check the timezone. Canvas shows deadlines in the timezone set on your account, which for an online programme is not always the one you are sitting in. An 11:59pm deadline can be 8:59pm where you are.
Do not wait for a perfect file. Upload what you have with ten minutes to spare, then replace it. The cost of a slightly worse submission is a few points; the cost of an upload failing at 11:58 is the whole penalty.
Getting an extension
Ask before the deadline, not after. Before, you are a student managing their workload; after, you are a student explaining a missed deadline, and those are received completely differently.
Be specific and brief: what you can deliver, and when. “Could I submit Thursday by 5pm” is answerable in one word. “I have been really overwhelmed” is not a request and puts the work of proposing something back on them.
Related
Late work usually comes from several things landing at once rather than one being too hard. And if you want to know what a penalty actually does to your final grade, the calculator will tell you.