Hey, i am a norwegian citizen and will land in HaNoi Vietnam on july 10th, (from bkk) I plan to just get a return ticket and visit on visa exemption, but wondering exactly which is the last day i can return on.

When i land on the 10th, can i have a return ticket on the 25th or 24th? or does it have to be on the 23th?

I think i got the answer:
"If you plan to travel to Vietnam for more than 15 days, you will need to apply for visa before traveling. The 15 days visa exemption starts on arrival date (day 1) when you pass through immigration. You need to exit Viet Nam (going through immigration) on the 15th day from the arrival date (day 1)."

So by landing on the 10th i need to have a return ticket on the 24th or before.