It takes 24 hours at least to get the COVID results. If I take the PCR test on Monday at 8AM, and get a negative result on Tuesday at 8AM, can I board a flight that departs on Friday at 8AM?

From Tuesday 8AM to Friday 8AM, exactly 72 hours.

However from Monday 8AM to Friday 8AM, it’s 86 hours.

So when does the clock start? From the time they took my sample nose swab? Or from the time they gave me the negative result?

  • 2
    Where are you going (is USA your destination or departure point)? Usually it's from the time of collection since processing times vary. If the USA is your destination, the date is calculated using calendar days, not hours, after the collection.
    – xngtng
    Oct 4, 2021 at 20:19
  • I don’t think I’ve ever seen a destination requiring a pre-departure PCR test that didn’t have the date the swab sample is given as the cut-off
    – Traveller
    Oct 4, 2021 at 22:26
  • 1
    For Germany, the PCR test must be taken 72 hours before the expected time of entry (an unexpected flight delay has no effect). 2021-09-08: Corona Tests für Reisende | Wann genau muss man sich vor Abreise testen lassen? Oct 5, 2021 at 4:55
  • Four days are 96 hours. not 86. Oct 5, 2021 at 9:03
  • Note that your premises are a bit incorrect: a PCR test can get your result in as little as 35 minutes (for example in the FRA airport, for 390€). Only the cheapo version takes ‘up to a day’, but even there usually less.
    – Aganju
    Oct 7, 2021 at 3:35

2 Answers 2


For travel TO the US you can find the detailed rules here. https://travel.state.gov/content/travel/en/international-travel/before-you-go/covid-19_testing_required_US_Entry.html

The sample must be taken 3 calendar days (NOT 72 hours) before departure. Departure is in most (but not all) cases the first leg of your flight. Example: if you are flying from Munich to Frankfurt to New York (on a single ticket with normal layovers) the "departure day" is determined by the time your flight from Munich is scheduled to depart.

So if you first leg departs Friday, the earliest you can a test is any time on Tuesday. It doesn't matter what time on Tuesday you take the test or what time on Friday your flight departs. Flights departing at 23:55 are great, flights departing at 00:10 not so much.

Things get a little more complicated if you take your test in a different time zone than your departure airport.

For travel FROM the US, the rules of the destination country and potentially the transit countries apply. These vary all over the place, so there is no single answer.


In the case of the US, according to the CDC:

  • the relevant time is that of the test, not of the result
  • the limit is 3 days calendar days before your flight, not 72 hours

So for a departure any time on Friday, you must take the test on Tuesday (at any time) or later.

  • That's correct if the OP is traveling to or through the US. That fact, however, is not addressed in the question. For other itineraries, the answer may be incorrect. Oct 4, 2021 at 23:12

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