The USA and Canada operate separate systems. Check the required travel document and record the departure deadline granted for each individual entry.
Travel days in North America run in two separate counts
Your travel days in North America run in two separate systems, one American, one Canadian. Time spent in one does not draw down the other, and neither authorisation carries across the border.
USA: the Visa Waiver Program
Up to 90 days per entry for tourism or business, with an approved ESTA. It cannot be extended, and a day of overstay costs you the programme for good.
USA: the I-94 is the record
The admission record CBP creates at entry states your permitted departure date, and that date governs. Pull it at i94.cbp.dhs.gov after you land.
Canada: eTA and the six months
An eTA is required to fly, and six months is the usual allowance. The officer may write a different date in your passport, in which case that one applies.
What a short hop does to travel days in North America
A run down to Mexico and back does not usually restart the American clock, because CBP counts neighbouring trips against the stay you are on. Canada may or may not stamp on your return. Note the dates yourself; without a stamp there is nothing else to go on.
What to check
- Does the authorisation match your passport and travel purpose?
- Which departure date was granted on this entry?
- Are side trips to neighbouring countries relevant to the same period?
- Have all actual entry and exit dates been recorded?