Free tool

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.

Happy Birthday Building Set

Checking

2321 Happy Birthday Building Set

33 pieces in 13 part and color combinations.

LEGO counts 32 pieces. This inventory comes from a separate parts catalog and lists 33; 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

Duplo, Quatro and Primo 32 pieces

  • Duplo Brick 2 x 2 Blue Part 3437 Element 343723 ×5
  • Duplo Brick 2 x 4 Blue Part 3011 Element 4290075 or 301123 ×2
  • Duplo Brick 2 x 4 x 2 with 2 x 2 Square Arch Blue Part 6394 Element 4267406 or 639423 ×1
  • Duplo Brick 2 x 2 Green Part 3437 Element 6528078 or 4583552 ×5
  • Duplo Brick 2 x 4 Green Part 3011 Element 4290071 or 301128 ×2
  • Duplo Brick 2 x 2 Red Part 3437 Element 4583321 or 343721 ×5
  • Duplo Brick 2 x 4 Red Part 3011 Element 4583326 or 4290074 ×2
  • Duplo Brick 1 x 2 x 2 with Three Balloons Print Yellow Part 4066pr0108 Element 82438 ×1
  • Duplo Brick 2 x 2 Yellow Part 3437 Element 4583546 or 343724 ×5
  • Duplo Brick 2 x 4 Yellow Part 3011 Element 4290060 or 301124 ×2
  • Duplo Brick 2 x 4 x 2 Rounded Ends with Monkey Face Print Yellow Part 4198pr9986 Element 82296 ×1
  • Duplo Car Base 2 x 6 with Open Hitch End and Red Wheels Yellow Part 2312c02 Element 6006222 or 4592297 ×1

Non-Buildable Figures (Duplo, Fabuland, etc) 1 piece

  • Duplo 2 x 2 x 2 Figure Brick, Spiky Bangs, Red Hair, Clown Make-up, with Button Suspenders Print Blue Part 2327c01pr0009 ×1

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.