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 counts 101 pieces. This inventory comes from a separate parts catalog and lists 100; 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.
Technic Axle 3 with StopReddish BrownPart 24316Element 6135494×1
Technic Special
4 pieces
Technic Ball Joint with Through Axle HoleBlackPart 53585Element 4286267×4
Projectiles / Launchers
3 pieces
Launcher, Brick Special 1 x 4 Spring Shooter with Light Bluish Gray TopDark Bluish GrayPart 15400Element 6324200 or 6048898×1
Projectile, Spring Shooter Ammunition 8L BarTrans-RedPart 15303Element 6287550 or 6054526×2
Technic Beams Special
3 pieces
Technic Beam 3 x 0.5 Liftarm with Boss and Pin Semi-ReducedBlackPart 33299bElement 4563044×2
Technic Beam 5 x 5 x 2 Perpendicular Fork 3 FingersDark Bluish GrayPart 19086Element 6102645×1
Technic Panels
3 pieces
Technic Panel Fairing #22 5L Small Smooth, Side ABlackPart 11947Element 6319983 or 6022761×1
Technic Panel Fairing #21 5L Small Smooth, Side BReddish BrownPart 11946Element 6179626×1
Technic Panel Fairing #22 5L Small Smooth, Side AReddish BrownPart 11947Element 6179618×1
Bricks Curved
2 pieces
Brick Curved 4 x 1 Double, No StudsBlackPart 93273Element 4613153×2
Plates
2 pieces
Plate 1 x 1BlackPart 3024Element 302426×2
Tiles Special
2 pieces
Tile Special 1 x 1 with Clip with Rounded EdgesBlackPart 15712Element 6335388 or 6066102×2
Bricks Round and Cones
1 piece
Cone 1 x 1 Inverted with Bar at Bottom (Ice Cream Cone)BlackPart 11610Element 6538443 or 6056234×1
Bricks Sloped
1 piece
Brick Sloped 30° 1 x 1 x 2/3 (Cheese Slope)BlackPart 54200Element 4504382 or 4287159×1
Pneumatics
1 piece
Pneumatic Hose Connector with Axle ConnectorDark Bluish GrayPart 99021Element 6265669 or 6020189×1
Tiles
1 piece
Tile 1 x 1 with GrooveBlackPart 3070bElement 307026×1
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.
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.