According to their website, they only release some tickets online, so "Sold Out" doesn't actually mean you can't go, only that the tickets released online have been sold out.
From the website they suggest their tickets may be bought out by scalpers:
Resellers of our entrance tickets are active on the internet. They buy
up our entrance tickets online, and attempt to sell them at a large
profit, often for double the price. This is not permitted. Do not buy
tickets from these organisations; you may be refused entry.
... and in the FAQ section...
I want to make a timed reservation using the online reservation system
on the website, but I see that very few times are left available. Is
the service really fully booked, or is there another way to make a
reservation? On the website you can see exactly what times are still
available. If you still want to come at a particular time for which no
more online tickets are available, then you can always buy tickets at
the Anne Frank House entry desk. However, you may have to wait in the
The place is almost always busy as noted by many reviews online and from my own experience as well.
Here are some tips (some are common sense):
- Summer months (especially July-August) will be a lot busier than other times of the year. Go in winter when people are less inclined to queue outside.
- Weekends will be busier than weekdays.
- Check the Opening Times and arrive a half-hour before opening (or earlier). The wait times later in the day can reach over 3 hours (in peak periods).
- Go in the evenings (after 5 or 6pm) when the queues are shorter. This won't work in Summer however.
- Some third parties may sell "general entrance tickets" but these won't let you skip the line, I think you need to exchange these at the ticket counter
- When purchasing tickets at the counter, they must be used then, so you can't purchase them for later in the day or another day
- You could try to join organised tours that claim they can skip the line.
- If you do manage to get a ticket online, this allows entry at a specific time on a particular day, and you won't have to wait in line, there is a separate entrance.
Finally if you do see a line, how long is the wait?
- Estimating the wait
How can you gauge your time? If the line is an L shape, ending just
along the Westerkerk, that’s about an hour. If the line is an L shape
but ends past the Westerkerk and at the Keizergracht canal, that’s two
hours. If the line is a Z and has now turned at the Keizergracht canal
and is running behind the Westerkerk, that’s three hours. Any longer,
well, you do the math.