How to catalogue a LEGO collection

A practical method for recording what LEGO sets you own: finding set numbers, dealing with unbuilt and partial sets, and keeping the list current without spreadsheets.

A collection you can search is worth more to you than one you remember. This is a method for cataloguing sets that takes an afternoon for a hundred sets and stays current afterwards. It uses this site's free tracker, but the steps work with a spreadsheet too.

1. Work from set numbers, not names

Names are ambiguous: the catalog has several sets called Millennium Falcon and dozens called Police Station. Numbers are not. Find the number on the box front, the instruction cover, or the barcode label, then add it. The guide to set numbers shows where to look and what the -1 suffix means.

2. Decide what "own" means before you start

Be consistent, or the count means nothing. A workable rule set:

• Built and complete: own it.
• Sealed and unbuilt: own it, note it as sealed.
• Disassembled into a bulk bin: own it if you still have the instructions and believe the parts are there; otherwise record the parts, not the set.
• Missing minifigures: still own the set; note which figures are gone. Set pages here list every figure a set came with, so the check is quick.

3. Add the sets you can see, then the ones you can prove

Start with built sets on shelves and sealed boxes: those are certain. Then go through instruction booklets; a booklet is good evidence you owned the set even if it is now in a bin. Leave sets you only remember for last, and mark them separately.

4. Record quantities

Duplicates matter, especially for small sets and battle packs bought in multiples. The tracker stores a quantity per set; a spreadsheet needs a column for it.

5. Keep a wishlist next to the collection

The most useful thing a catalogue does is answer "do I already have this?" in a shop. The second most useful is "what was I looking for?". Keep both lists in the same place so one search answers both.

6. Export it, and keep the export

Whatever you use, take a copy out of it. The tracker exports the collection as a CSV file from the Collection tab; that file is what you hand an insurer, and it is your backup if the site or your device goes away. An export lists set numbers, names, years, piece counts and quantities: facts, not the site's value estimates.

7. Sync it across devices, if you want

The tracker works without an account, stored in the browser you used. A free account syncs the same list between a phone and a computer and lets you publish a share page listing what you own, which is handy for trades and for relatives who want to buy the right thing. Value estimates never appear on a share page.

What not to bother with

• Cataloguing individual parts of complete sets. The catalog already knows them.
• Recording a "value" for each set. Whatever number you write down will be wrong within a year, and this site's estimates are labelled estimates for that reason.
• Photographing every box. One photo of each shelf is enough for insurance if the list itself is accurate.

The catalog here covers 18,273 sets from 1949 onwards, so anything you own should be findable by number. If it is not, the contact page is the place to say so.

Questions people ask

What is the fastest way to identify a LEGO set I own?

The set number on the box or the instruction cover. Search it, confirm the picture matches, and add it. Names are ambiguous; numbers are not.

Should I count a set I took apart?

Only if you still have the instructions and believe the parts are together. Otherwise record it as parts. Whichever rule you choose, apply it to every set.

How do I back up my collection list?

Export it as a CSV from the Collection tab and keep the file. It lists numbers, names, years, piece counts and quantities.

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