BlockTalk Find Your Set

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LEGO Missing Piece Checker

Rule out the usual hiding places first. If the piece really is gone, check the set piece by piece and leave with the element ID LEGO asks for, or a link to buy the part.

Basic Building Set

Checking

503 Basic Building Set

39 pieces in 19 part and color combinations.

LEGO counts 35 pieces. This inventory comes from a separate parts catalog and lists 39; the two do not always count the same elements, so their totals differ. Spare parts are counted in neither figure.

Before you call it missing

Builders who report a missing piece often find it in one of these places. Tick each one off as you look.

Show

Piece checklist

Red 13 pieces

  • Brick 1 x 2 Red Part 3004 Element 4613961 or 300421 ×4
  • Brick 2 x 2 Red Part 3003 Element 4103590 or 300371 ×2
  • Brick 2 x 4 Red Part 3001 Element 300121 ×1
  • Plate 2 x 2 Red Part 3022 Element 4613974 or 302221 ×1
  • Plate 2 x 4 Red Part 3020 Element 302021 ×2
  • Plate 2 x 8 Red Part 3034 Element 303421 ×3

Yellow 10 pieces

  • Brick 1 x 2 Yellow Part 3004 Element 4613966 or 300424 ×3
  • Brick 1 x 4 Yellow Part 3010 Element 301024 ×2
  • Brick 2 x 2 Yellow Part 3003 Element 4103588 or 300374 ×2
  • Brick 2 x 4 Yellow Part 3001 Element 300124 ×1
  • Brick Sloped 45° 2 x 2 Yellow Part 3039 Element 303924 ×2

Blue 8 pieces

  • Brick 1 x 2 Blue Part 3004 Element 4613959 or 300423 ×3
  • Brick 2 x 2 Blue Part 3003 Element 4103589 or 300373 ×1
  • Brick 2 x 4 Blue Part 3001 Element 300173 or 300123 ×1
  • Plate 2 x 2 Blue Part 3022 Element 4613973 or 302223 ×1
  • Plate 2 x 3 Blue Part 3021 Element 302123 ×2

Black 6 pieces

  • Brick Special 2 x 2 [Red Wheels for Single Tyre] Black Part 3137c01 ×2
  • Tyre 15 x 6 Offset Tread Small Black Part 3641 Element 4501046 or 364126 ×4

Trans-Clear 2 pieces

  • Brick Sloped 45° 2 x 2 Trans-Clear Part 3039 Element 6514100 or 6244886 ×2

Tick each piece as you find it, or mark it missing.

When a piece really is missing

Ask LEGO

LEGO takes requests for pieces missing from a new set through its customer service site. The form asks for the set number and each piece's element ID, the number printed beside the piece in the parts list at the back of the instructions. This checker lists both.

Request a replacement from LEGO

Buy the piece

Mark a piece missing and your list links it to an eBay search for that part, which also covers pieces from older or second-hand sets.

Keep a record

Copy or download your missing list (the CSV opens in any spreadsheet), or print the whole checklist and tick pieces off on paper. Your marks stay in this browser, so you can check a big set over several sittings.

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