How to find a LEGO set number
The set number is on the front of the box and on the cover of the instructions. With neither, find it by theme and year.
1
Look at the box
The set number is printed on the front of the box, usually in a corner next to the age mark and piece count.
2
Check the instructions
Every instruction booklet shows the number on its cover and on the back page.
3
No box? Browse by theme and year
If you know roughly when you got it, open the theme and walk the shelf of that year. The pictures make it quick to spot.
4
Search by name
Type a word from the set, like Falcon or Hogwarts, into the lookup.
Open the set lookup Browse themes
Questions
Can I find a LEGO set from a minifigure?
Yes. Open the theme the minifigure belongs to and check the sets of the years it was sold; each set page lists its minifigures.