passed vs. past
The test here is unusually clean: "passed" is only ever a verb, and "past" is never one. If the word is doing something in the sentence, it takes the double "s." Everything else — time gone by, going by something, the previous version — takes "past."
passed
The past tense and past participle of the verb "pass." Always a verb.
- She passed the exam on the second attempt.
- We passed the deadline without noticing.
- The motion passed by a single vote.
- He has passed every audit since 2019.
past
A noun, adjective or preposition. Time gone by, or movement beyond something. Never a verb.
- In the past, we handled this by hand.
- Past performance is no guarantee.
- The office is just past the bridge.
- It's half past four.
Why passed and past get mixed up
Passed and past sound identical and both come from the verb pass, which is why they are easy to swap. The difference is the job each one does in the sentence.
Passed is only ever the verb: the past tense of pass. It needs a subject that did the passing: she passed the exam, time passed slowly, the bill passed the Senate. Past is everything else. It can be a noun (in the past), an adjective (the past week), a preposition (walk past the bank) or an adverb (the car drove past).
A reliable test is to change the tense. If you can turn the sentence into the present with "passes" and it still works, you want passed. "The deadline passes" works, so "the deadline passed". "We drive passes the station" does not, so it is "we drove past the station".
Common mistakes
The deadline has already past.
✓The deadline has already passed.
This is the verb: the deadline passes, so it has passed.
We drove passed the station twice before we found it.
✓We drove past the station twice before we found it.
Past here means beyond; the verb in the sentence is drove.
The last three weeks have past quickly.
✓The last three weeks have passed quickly.
The weeks are doing the passing, so the verb: passed.
Quick way to remember
Ask whether the word is an action. Actions take "passed" — she passed, the motion passed. If the word describes time, position, or something previous, it takes "past." When in doubt, try replacing it with "went by": if that works as a verb, use "passed."
Questions
Is it "past due" or "passed due"?
Past due. It describes a bill that is beyond its due date, which is the adjective past.
Is it "passed away" or "past away"?
Passed away. It is the verb pass, meaning died.