How LEGO set numbers work

Where to find a LEGO set number, what the digits do and do not mean, why the catalog writes 75192-1, and which number ranges belong to which themes.

Every LEGO set has a number, and it is the most reliable way to identify one. Names get reused, translated and shortened; numbers do not. This guide covers where the number is printed, what the digits do and do not tell you, and why catalogs like this one write 31203-1 rather than 31203.

Where to find the number

• On the box: the front, usually near a corner, in large type, and again on the side panels and the barcode label.
• On the instruction booklet: the front cover, and the back cover next to the barcode.
• On LEGO.com and shop listings: in the product title and the URL.
• Not on the bricks. Elements carry part numbers, not set numbers, so a loose pile of bricks cannot be traced to a set by its markings alone.

If you have the number, search it here and the set page shows the piece count, minifigures, year and theme.

What the digits mean

A set number is an identifier, not a code. There is no scheme where one digit means the theme and another the year. What does exist is a pattern: LEGO assigns numbers in blocks, so sets in the same theme and era tend to share a prefix. The table below is computed from the 7,541 five-digit set numbers in the catalog: for each two-digit prefix with at least 100 sets, the most common theme and how much of the block it takes.

A prefix is a tendency, not a rule. The 60xxx block is almost all City; the 30xxx block is small polybag-sized sets spread across many themes; the 40xxx block is dominated by seasonal and promotional sets. When a theme runs out of numbers in its block it gets another one, which is why Star Wars sets appear under 75xxx and, for a while, under 7xxx.

Four digits, five digits, and everything else

• 6,418 sets in the catalog have four-digit numbers. These are mostly older sets, from the 1970s through the mid 2000s.
• 7,541 have five-digit numbers, the format LEGO has used for most sets since the late 2000s.
• 4,314 have something else: one to three digits from the earliest decades, letters, or dotted numbers such as 700.3. The catalog keeps them as printed.

The "-1" suffix

Catalogs built on the Rebrickable database write every set number with a suffix: 31203-1, not 31203. The suffix separates releases that share a number. The first release is -1; a re-issue, a regional variant or a differently packed version of the same number gets -2, -3 and so on. 1,833 sets in the catalog carry a suffix above 1. For example, Window Exploration Bag (2000409-2) shares its number with Window Exploration Bag (2000409). When you search this site you can type the number with or without the suffix; the page for the -1 release is what you want unless you know you have a variant.

Does a bigger number mean a bigger set?

No. The five largest sets in the catalog by piece count are World Map (31203), Eiffel Tower (10307), The Ultimate Battle for Chima (BIGBOX), Titanic (10294), Colosseum (10276). Their numbers come from different blocks and say nothing about size. Piece count, year and theme are on every set page, and the biggest sets ranking lists them in order.

Questions people ask

Is 75192 the same set as 75192-1?

Yes. 75192 is the number LEGO prints; 75192-1 is how catalogs based on the Rebrickable database write the first release of that number. A -2 or higher marks a re-issue or variant of the same number. 1,833 of the 18,273 sets here carry a suffix above 1.

Can I identify a set from its bricks?

Not from markings. LEGO elements carry part numbers and mould marks, not the set number. If you know the parts you have, a parts inventory search on Rebrickable can suggest sets that contain them; if you know the set's name or theme, searching here narrows it quickly.

Do set numbers ever get reused for different sets?

The same number is only reused for variants and re-issues of the same product, which the catalog separates with the -2, -3 suffix. Different products get different numbers.

Set data from the Rebrickable database, refreshed daily. Figures on this page are computed from the catalog dated 2026-09-01.