Most Lego pieces can be identified in a minute once you know which number you are looking at. Look for the small design number moulded into the part, add the colour, and you can find it in any catalogue; if there is no number, a photo search with Brickognize usually gets you to the right BrickLink page.
The catch is that Lego, BrickLink and Rebrickable do not always use the same numbers or colour names. Below, we explain the three numbers you will meet, show four common parts with their real IDs in each system, and give a colour chart that translates Lego's names into the names marketplaces use. In October 2026 we checked every number in this guide against Lego's element records, as shown on Brickset, and against the BrickLink and Rebrickable catalogues.
Design ID, element ID and set number
Three numbers get mixed up all the time, and each answers a different question.
- Design ID: the shape. A 2 × 4 brick is 3001 in every colour. Lego moulds this number, usually four or five digits, into many parts. It is tiny, so hold the piece under bright light and turn it until the digits become readable. A phone camera with zoom works better than squinting.
- Element ID: the shape in one specific colour, and on printed parts one specific print. A red 2 × 4 brick is 300121, a black one 300126. You find element IDs in the parts list at the back of newer instruction booklets, not on the piece itself.
- Set number: the box. 10333 is a set, not a part, and the instruction booklet carries yet another number of its own.
Older element IDs follow a simple pattern: design ID plus Lego's colour number. 300121 is design 3001 plus colour 21, which Lego calls Bright Red. Newer element IDs are seven-digit numbers with no visible logic. The same 2 × 4 brick in Medium Stone Grey is 4211385. So you can sometimes read the shape out of an old element ID, but never rely on it for a new one.
The number on the brick is the design ID, not the element ID. Since the design ID says nothing about colour, you always need to choose the colour separately when you search with it.
How to identify a Lego piece step by step
Work through these in order. Most pieces are solved by step one or two.
- Read the part. Check the underside, the inside of tubes and the back of flat surfaces for a moulded number. Very small parts often have no room for one, and on worn or old pieces the digits can be hard to read.
- Use the set's parts list. If you know which set the piece came from, the inventory at the back of the instructions shows a picture of every element with its element ID and quantity. The PDF instructions on Lego's website include the same list. Our guide to finding Lego instructions for any set explains where to get them. Many older booklets have no parts list at all; for those, use the set inventories on BrickLink, Rebrickable or Brickset.
- Search by shape. No number and no set? Describe the part the way catalogues do. Count the studs in each direction, then decide the category: a brick is three plates high, a plate is one third of that, and a tile is a plate with no studs on top. "Plate 1 x 2" or "slope 45 2 x 2" finds the part faster than a description in your own words. The exact measurements in millimetres are in our guide to Lego brick dimensions.
- Search by photo. For prints, minifigure parts and odd shapes, a photo search is usually quicker. We cover the tools further down.
Whatever route you take, confirm the result against the catalogue drawing before you order. A thumbnail that looks right can be a different mould with a small change, such as a tile with or without a groove along the bottom edge.
Four common Lego pieces and their numbers
Here is how one part appears in each system. Lego's design ID is what is moulded on the piece; BrickLink and Rebrickable are the two big fan catalogues.
| Part | Lego design ID | BrickLink number | Rebrickable number | Element IDs (Lego colour name) |
|---|---|---|---|---|
| Brick 2 × 4 | 3001 | 3001 | 3001 | 300121 Bright Red, 300126 Black, 4211385 Medium Stone Grey |
| Round plate 1 × 1 | 6141 (transparent: 30057) | 4073 | 6141 | 614126 Black, 4211525 Medium Stone Grey, 4210633 Dark Stone Grey |
| Tile 1 × 2 with groove | 3069 (transparent: 30070) | 3069 | 3069b | 306926 Black, 4211414 Medium Stone Grey, 4211052 Dark Stone Grey |
| Minifigure torso, printed | 76382 | 973 plus a print code | 973c… plus a print code | 6490187 Black, print no. 7114 |
Brick 2 × 4: the easy case
Design 3001 is the same number at Lego, BrickLink and Rebrickable, which is why it is the classic example. Lego's own name for it is "BRICK 2X4", while BrickLink writes "Brick 2 x 4". If your search on Lego's site fails, try Lego's short uppercase naming style instead of the marketplace one.
Round plate 1 × 1: Lego says 6141, BrickLink says 4073
This is the part that confuses most people. Lego's records list the 1 × 1 round plate as design 6141, and Rebrickable follows that. BrickLink files it under 4073 and lists 6141 as an alternate number, so searching for 6141 on BrickLink still gets you there if you use the catalogue search. The transparent versions carry yet another Lego design ID, 30057, because Lego numbers some transparent parts separately. On BrickLink they sit under the same 4073 page.
Tile 1 × 2: one letter of difference
Lego and BrickLink both use 3069 for the 1 × 2 tile with a groove along the bottom edge. Rebrickable calls it 3069b to separate it from an old version without the groove. If a list from Rebrickable says 3069b, it is the same tile you find under 3069 on BrickLink and at Lego. Again, transparent tiles have their own Lego design ID, 30070.
Minifigure torso: the print decides
Lego gives printed minifigure torsos one shared design ID, 76382. Lego's element name is generic too: element 6490187 is called "MINI UPPER PART, NO. 7114". Rebrickable lists thousands of different torsos under that one design ID. For a torso, the design ID only tells you the shape, so you need the element ID from the instructions, or the print-specific numbers that BrickLink and Rebrickable add to their base numbers. BrickLink builds torso numbers from 973, a print code and an arm suffix; Rebrickable uses 973c followed by codes for the arms, hands and print. In our experience, a photo search is the fastest route for torsos, heads and legs, because the print is what the image recognition reads.
Lego colour names vs BrickLink and Rebrickable
Lego has its own colour names and numbers. BrickLink and Rebrickable use their own names, which most sellers and builders also use. Pick a Brick shows Lego's names; BrickLink, Brick Owl and most sellers show BrickLink's. That is why someone looking for "Light Bluish Gray" on Lego's site finds nothing: Lego calls it Medium Stone Grey.
A few names are traps. Lego's Dark Green is plain "Green" on BrickLink, while BrickLink's "Dark Green" is Lego's Earth Green. BrickLink's "Brown" is an old colour Lego called Earth Orange, not today's Reddish Brown. And "Tan" is Lego's Brick Yellow.
| Lego name (Lego no.) | BrickLink name (ID) | Rebrickable ID |
|---|---|---|
| White (1) | White (1) | 15 |
| Black (26) | Black (11) | 0 |
| Bright Red (21) | Red (5) | 4 |
| Bright Blue (23) | Blue (7) | 1 |
| Bright Yellow (24) | Yellow (3) | 14 |
| Dark Green (28) | Green (6) | 2 |
| Earth Green (141) | Dark Green (80) | 288 |
| Brick Yellow (5) | Tan (2) | 19 |
| Sand Yellow (138) | Dark Tan (69) | 28 |
| Reddish Brown (192) | Reddish Brown (88) | 70 |
| Medium Stone Grey (194) | Light Bluish Gray (86) | 71 |
| Dark Stone Grey (199) | Dark Bluish Gray (85) | 72 |
| New Dark Red (154) | Dark Red (59) | 320 |
| Earth Blue (140) | Dark Blue (63) | 272 |
| Bright Orange (106) | Orange (4) | 25 |
| Flame Yellowish Orange (191) | Bright Light Orange (110) | 191 |
| Bright Yellowish Green (119) | Lime (34) | 27 |
| Sand Green (151) | Sand Green (48) | 378 |
| Grey (2), old | Light Gray (9) | 7 |
| Dark Grey (27), old | Dark Gray (10) | 8 |
| Earth Orange (25), old brown | Brown (8) | 6 |
Rebrickable uses BrickLink's colour names in almost every case but has its own ID numbers, so a colour ID copied from one site means nothing on the other. Lego's colour number is the one that appears at the end of old element IDs: 21 in 300121 is Bright Red.
Old grey or new grey?
The last three rows matter for anyone sorting older collections. Lego replaced its old greys and its old brown with the bluish greys and Reddish Brown in the 2000s. BrickLink records the old Light Gray up to 2007 and the old Dark Gray and Brown up to 2006. On their own, old and new greys are easy to mix up. Next to each other, the difference is clear, so keep one part of known colour from a recent set as a reference.
Faded and yellowed parts
Colour is the least reliable clue on used parts. White and light grey yellow in sunlight, and a yellowed white piece can look like a different colour entirely. Shades also vary slightly between production batches, even within one set. Judge the colour in daylight, look at the side that was hidden from the sun, and compare it with a reference part rather than with a screen.
Identify Lego pieces from a photo
Image recognition has become good enough to be the first step for prints and minifigure parts. Use it to get a number, then confirm that number in a catalogue. Finding out which figure is inside a sealed Collectible Minifigures box is a different task, covered in our guide to the Lego minifigure scanner.
Brickognize: one part, one photo
Brickognize runs in the browser, so you do not need to install an app. You photograph or upload a single part, minifigure or set, and it suggests matches with a confidence indicator, a suggested colour and a direct link to the BrickLink page. We use it ourselves, and it is impressively reliable for common parts and for sorting minifigure heads, torsos and legs that have been swapped between figures. It does miss things: new prints and unusual heads or torsos sometimes return nothing useful. When that happens, browse the part category on BrickLink by shape.
For the best result, photograph one part on a plain, light background with the top or most distinctive side facing the camera. If the first suggestion looks wrong, try a second angle.
Brickit: scanning a whole pile
Brickit is an app for iOS and Android with a different goal. You spread a pile of loose bricks on the floor, scan it, and the app recognises the pieces and suggests models you can build from them. It can also keep a digital inventory of sorted parts. The download is free, with a paid Pro tier for more features. Brickit is aimed at building ideas and sorting, not at telling you the exact element ID of one rare piece, and we have not tested it in depth.
Google Lens and similar tools
A general image search can tell you roughly what kind of part you hold, for example a hinge plate or a curved slope. It rarely gives you the exact number. Use it to learn the name, then search that name in a Lego catalogue.
From number to part: where to look it up
Once you have a number, these are the places to use it:
- Lego Pick a Brick: search by element ID or design ID to see whether Lego still sells the part. The list upload works with Lego's element IDs, so a list exported from BrickLink needs converting first. Our Pick a Brick guide covers ordering and fees.
- Lego replacement parts: for pieces missing or broken in a new set. The form accepts element and design IDs. Our comparison of replacement services and parts shops explains when a part is free and when you buy it.
- BrickLink: shows every set a part appeared in, its colours and current offers from sellers.
- Rebrickable: shows which sets contain a part and can work out which sets you could build from the parts you already own.
- Brickset: looks up Lego's own element records, including Lego's name, design ID and colour for an element ID.
Some parts turn out to be worth far more than a common brick. If you have identified an unusual print or an old colour, check our list of rare Lego pieces before you sell it in a bulk lot.
Identify Lego pieces FAQ
Where is the number on a Lego piece?
On many parts, a four- or five-digit design ID is moulded on the underside, inside a tube or on the back of a flat surface. It is small and easiest to read under bright light. Very small parts often have no number.
What is the difference between a design ID and an element ID?
The design ID describes the shape, such as 3001 for a 2 × 4 brick. The element ID describes that shape in one colour or print, such as 300121 for a red 2 × 4 brick. The design ID is on the piece, the element ID is in the instructions.
Why does BrickLink use a different number than Lego?
BrickLink's catalogue was built by its users and keeps its own numbering. Most common parts match Lego's design ID, but some do not: the 1 × 1 round plate is 6141 at Lego and 4073 on BrickLink. BrickLink usually lists Lego's number as an alternate, so a catalogue search still finds the part.
Can I identify a Lego piece from a photo?
Yes. Brickognize identifies single parts and minifigure pieces from a photo in the browser and links to BrickLink. Check the suggested number and colour against the catalogue before ordering.
The short version
- Number on the part: that is the design ID. Add the colour and search.
- Set known: take the element ID from the parts list at the back of the instructions.
- No number, no set: count studs, name the category and search, or use Brickognize.
- Colour names differ: Lego's Medium Stone Grey is BrickLink's Light Bluish Gray, and the chart above covers the rest.
- Confirm the number in a catalogue before ordering, then buy through Pick a Brick, the replacement service or a marketplace.
