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.
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
3 pieces
Technic Beam 1 x 2 ThinBlackPart 41677Element 6338428 or 4167726×1
Technic Beam 1 x 2 ThinWhitePart 41677Element 6371416 or 4163533×2
Tiles
3 pieces
Tile 1 x 1 with GrooveWhitePart 3070bElement 6550138 or 3070011 spare in the box×3
Bricks Curved
2 pieces
Brick Curved 4 x 1 Double, No StudsWhitePart 93273Element 6552143 or 6023806×2
Plates
2 pieces
Plate 1 x 1WhitePart 3024Element 6548262 or 3024011 spare in the box×2
Technic Bushes
2 pieces
Technic BushLight Bluish GrayPart 3713Element 6275844 or 62718171 spare in the box×1
Technic Bush 1/2 Smooth with Axle Hole Semi-ReducedLight Bluish GrayPart 32123bElement 6271165 or 42115731 spare in the box×1
Bricks Sloped
1 piece
Brick Sloped 18° 2 x 1 x 2/3 with 4 Slots / GrateWhitePart 61409Element 6552142 or 6023804×1
Plates Special
1 piece
Plate Special 1 x 2 with Handle on End [Closed Ends]WhitePart 60478Element 6552131 or 4515364×1
Technic Beams Special
1 piece
Technic Beam 1 x 3 with Ball Joint in MiddleDark Bluish GrayPart 98577Element 6001085×1
Technic Special
1 piece
Technic Tooth 1 x 3 with Axle Hole [Rounded Underside]WhitePart 41669Element 4173941×1
Tiles Special
1 piece
Tile Special 1 x 1 with Clip with Rounded EdgesWhitePart 15712Element 6348055 or 6054551×1
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.