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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.

LEGO Design Seminar Set 2025

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40231 LEGO Design Seminar Set 2025

163 pieces in 47 part and color combinations, plus 3 minifigures.

The piece count includes the 12 parts inside the set's minifigures, which this inventory lists separately. 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.

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Piece checklist

Black 74 pieces

  • Brick Curved 1 x 2 x 1 1/3 with Curved Top Black Part 6091 Element 6383142 or 6184784 ×8
  • Brick Curved 2 x 4 x 1 1/3 Black Part 6081 Element 6174252 or 4125550 ×4
  • Brick Round 4 x 4 Centre Hole Black Part 87081 Element 4558957 ×1
  • Brick Round, Curved 2 x 2 x 1 1/3, Corner Black Part 67810 Element 6359039 ×4
  • Brick Sloped 30° 1 x 2 x 2/3 Black Part 85984 Element 4548180 ×3
  • Brick Sloped Inverted 45° 2 x 1 with 2/3 Cutout Black Part 2310 Element 6465248 ×7
  • Hinge Brick 1 x 2 Base Black Part 3937 Element 393726 ×1
  • Hinge Brick 2 x 2 Top Plate Thin Black Part 6134 Element 4124096 or 613426 ×2
  • Panel 1 x 2 x 1 [Rounded Corners] Black Part 4865b Element 6146220 ×1
  • Plate 2 x 2 Black Part 3022 Element 302226 ×1
  • Plate 2 x 3 Black Part 3021 Element 302126 ×2
  • Plate 2 x 4 Black Part 3020 Element 302026 ×7
  • Plate 8 x 8 Black Part 41539 Element 4166619 ×2
  • Plate Round 4 x 4 with Pin Hole Black Part 60474 Element 4515350 ×1
  • Plate Special 1 x 1 with Clip Light, Bar Hole [Thick Ring] Black Part 4081b Element 6281993 or 4632571 ×1
  • Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper) Black Part 15573 Element 6092585 ×2
  • Plate Special 1 x 2, Top Clip [Open O] Black Part 44861 Element 6347310 ×2
  • Plate Special 2 x 2 with Groove and Center Stud (Jumper) Black Part 87580 Element 6663108 or 4565323 ×5
  • Plate Special 2 x 2 with Horizontal T-Bar Underneath Black Part 5066 Element 6488003 ×1
  • Tile 1 x 1 with Groove Black Part 3070b Element 307026 ×2
  • Tile 1 x 3 Black Part 63864 Element 4558170 ×4
  • Tile 1 x 4 with Groove Black Part 2431 Element 243126 ×1
  • Tile 2 x 2 with Groove Black Part 3068b Element 306826 ×2
  • Tile 2 x 4 with Groove Black Part 87079 Element 4560182 ×1
  • Turntable 4 x 4 Square Base, Locking Black Part 61485 Element 4517986 ×1
  • Wedge Plate 4 Stud 45° Angle Plate Black Part 15706 Element 6054852 ×8

Blue 36 pieces

  • Brick Curved 2 x 1 No Studs [1/2 Bow] Blue Part 11477 Element 6055065 ×4
  • Brick Wedged, Curved 2 x 1 with Stud Notch Left Blue Part 29120 Element 6172414 ×4
  • Plate 1 x 2 Blue Part 3023 Element 302323 ×4
  • Plate 1 x 8 Blue Part 3460 Element 346023 ×2
  • Tile 1 x 2 with Groove Blue Part 3069b Element 306923 ×1
  • Tile 1 x 2 with Stud Notch Left Blue Part 5091 Element 6535148 ×4
  • Wedge Plate 2 x 2 Left Blue Part 24299 Element 6189198 ×7
  • Wedge Plate 3 x 2 Right Blue Part 43722 Element 4498155 or 4280149 ×10

Dark Azure 36 pieces

  • Brick Curved 2 x 1 No Studs [1/2 Bow] Dark Azure Part 11477 Element 6137300 ×4
  • Brick Wedged, Curved 2 x 1 with Stud Notch Left Dark Azure Part 29120 Element 6211418 ×4
  • Plate 1 x 2 Dark Azure Part 3023 Element 4653988 ×4
  • Tile 1 x 2 with Stud Notch Left Dark Azure Part 5091 Element 6551377 ×4
  • Wedge Plate 2 x 2 Left Dark Azure Part 24299 Element 6145416 ×8
  • Wedge Plate 3 x 2 Right Dark Azure Part 43722 Element 6565474 or 6167073 ×12

Trans-Clear 11 pieces

  • Bar, Angled with 1 x 1 Round Plate / Stud on End Trans-Clear Part 65578 Element 6510188 or 6285587 ×6
  • Brick Round 1 x 1 Open Stud Trans-Clear Part 3062b Element 6514232 or 6223655 ×5

Medium Azure 2 pieces

  • Plate 1 x 6 Medium Azure Part 3666 Element 6603312 or 4625036 ×2

Opal Trans-Dark Pink 1 piece

  • Plant, Fern 2 x 3 x 2 Opal Trans-Dark Pink Part 2682 Element 6581714 or 6442196 ×1

Red 1 piece

  • Brick 2 x 2 Red Part 3003 Element 4103590 or 300371 ×1

Trans-Light Blue 1 piece

  • Plate Round 1 x 1 with Open Stud Trans-Light Blue Part 85861 Element 6510163 or 6283590 ×1

Yellow 1 piece

  • Animal, Bird, Duck / Duckling with Black Eyes, Orange Beak Yellow Part 49661pr0001 Element 6269141 ×1

Minifigures 3 figures

  • Dark Purple Torso, Sand Blue Legs, Reddish Brown Hair Minifigure, checked as a whole figure ×1
  • Red Torso, Black Legs, Black Hat Minifigure, checked as a whole figure ×1
  • Medium Lavender Suit, Trans-Pink Hair Minifigure, checked as a whole figure ×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.

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