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.

Robot Inventor

Checking

51515 Robot Inventor

949 pieces in 145 part and color combinations.

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

Black 371 pieces

  • Antenna 8H Whip Black Part 2569 Element 6265148 or 6164379 ×2
  • Brick Round 1 x 1 diameter Tube with 90 Degree Elbow (2 x 2 x 1) and Axle Holes (Crossholes) at each end Black Part 25214 Element 6179182 ×8
  • Large Figure Weapon, Barrel with 2 Pin Holes and 3 Axle Holes Black Part 98585 Element 6186133 or 6156897 ×6
  • Technic Axle 12 Black Part 3708 Element 370826 ×2
  • Technic Axle 4 Black Part 3705 Element 370526 ×4
  • Technic Axle 8 Black Part 3707 Element 370726 ×2
  • Technic Axle Connector Double Flexible [Rubber] Black Part 45590 Element 4198367 ×4
  • Technic Axle Connector with Axle Hole [Reinforced] Black Part 42135 Element 6331716 ×3
  • Technic Axle and Pin Connector Angled #6 - 90° Black Part 32014 Element 6268905 or 4107767 ×1
  • Technic Axle and Pin Connector Perpendicular 3L with Centre Pin Hole Black Part 32184 Element 6276951 or 4121667 ×2
  • Technic Axle and Pin Connector Perpendicular Double Black Part 32291 Element 6280394 or 4140430 ×8
  • Technic Axle and Pin Connector Perpendicular Double Split Black Part 41678 Element 4162857 ×4
  • Technic Beam 1 x 11 Thick Black Part 32525 Element 6029578 or 4534909 ×7
  • Technic Beam 1 x 11.5 Double Bent Thick Black Part 32009 Element 6271152 or 4111998 ×8
  • Technic Beam 1 x 15 Thick Black Part 32278 Element 4542573 or 4128603 ×5
  • Technic Beam 1 x 2 Thick with Pin Hole and Axle Hole Black Part 60483 Element 6265091 or 6006140 ×2
  • Technic Beam 1 x 3 Thick Black Part 32523 Element 4142822 or 3252326 ×10
  • Technic Beam 1 x 5 Thick Black Part 32316 Element 4142135 or 4140429 ×7
  • Technic Beam 1 x 5 Thin with Axle Holes on Ends Black Part 11478 Element 6327028 or 6030286 ×4
  • Technic Beam 1 x 7 Bent (4 - 4) Thick Black Part 32348 Element 6278125 or 4128593 ×9
  • Technic Beam 1 x 7 Thick Black Part 32524 Element 4495935 or 4155458 ×11
  • Technic Beam 1 x 9 Bent (7 - 3) Thick Black Part 32271 Element 6276835 or 4140327 ×4
  • Technic Beam 2 x 4 L-Shape Thick Black Part 32140 Element 6271825 or 4120017 ×6
  • Technic Beam 3 x 5 L-Shape Thick Black Part 32526 Element 4142823 or 3252626 ×12
  • Technic Beam Frame 11 x 15 Black Part 39790 Element 6295161 ×2
  • Technic Beam Frame 5 x 7 with 3 x 5 Opening Thick Black Part 64179 Element 6016154 ×5
  • Technic Beam Frame 7 x 11 Black Part 39794 Element 6265643 ×2
  • Technic Gear 12 Tooth Double Bevel Black Part 32270 Element 4177431 ×4
  • Technic Gear 36 Tooth Double Bevel Black Part 32498 Element 4255563 or 4177434 ×1
  • Technic Pin Connector Hub with 1 Axle Black Part 22961 Element 6253260 ×4
  • Technic Pin Connector Hub with 2 Perpendicular Axles Black Part 10197 Element 6099801 or 6098801 ×2
  • Technic Pin Connector Perpendicular Long Black Part 32557 Element 4143466 ×4
  • Technic Pin Connector Round 1L [Beam] Black Part 18654 Element 6121485 1 spare in the box ×6
  • Technic Pin Connector Round [Slotted] Black Part 62462 Element 6173119 or 4526982 ×8
  • Technic Pin with Friction Ridges Lengthwise and Center Slots Black Part 2780 Element 4121715 or 278026 5 spares in the box ×175
  • Technic Pin with Friction Ridges Lengthwise and Towball - Round Pin Hole Black Part 66906 Element 6344752 ×4
  • Technic Turntable Large Type 4 Top, 60 Tooth Black Part 88738 Element 6413529 ×1
  • Technic Turntable Small Base, 28 Tooth Black Part 99010 Element 6326620 or 4652236 ×2
  • Tile 1 x 2 with Groove Black Part 3069b Element 306926 ×2
  • Tile 1 x 6 with Groove Black Part 6636 Element 663626 ×2
  • Tile 1 x 8 with Groove Black Part 4162 Element 416226 ×2
  • Tyre Offset Tread with Center Band 23 x 7 Black Part 61254 Element 4541455 ×4
  • Wheel 18 x 14 with Pin Hole Black Part 55889 Element 6273330 ×4
  • Wheel 57 x 14 with 4 Spokes with 2 Holes and Black Integral Tire Black Part 39367pat0002 Element 6460559 or 6287602 ×6

Blue 144 pieces

  • Technic Axle Pin with Friction Ridges Lengthwise Blue Part 43093 Element 4309323 or 4206482 ×60
  • Technic Beam 1 x 3 Thick Blue Part 32523 Element 4509376 or 4144284 ×2
  • Technic Pin Long with Friction Ridges Lengthwise, 2 Center Slots Blue Part 6558 Element 4514553 ×82

Light Bluish Gray 128 pieces

  • Differential Gear House Light Bluish Gray Part 65414 Element 6285647 ×1
  • Hose Rigid 3mm D. 8L / 6.4cm Light Bluish Gray Part 75c08 Element 4514192 ×2
  • Motor, Medium Servo SPIKE Light Bluish Gray Part 54696 Element 6359216 or 6299648 ×4
  • Plate Special 2 x 2 with Pin on Bottom Light Bluish Gray Part 2476a Element 6276848 or 4237084 ×2
  • Projectile, Arrow with Shaft, Hollow Black Rubber End Light Bluish Gray Part 46537 Element 6307940 ×2
  • Technic Axle 3 Light Bluish Gray Part 4519 Element 4211815 ×9
  • Technic Axle 7 Light Bluish Gray Part 44294 Element 44294194 or 4211805 ×4
  • Technic Axle and Pin Connector Perpendicular 3L with Centre Pin Hole Light Bluish Gray Part 32184 Element 6276969 or 4211621 ×6
  • Technic Axle and Pin Connector Perpendicular Double 4L Light Bluish Gray Part 98989 Element 6308440 or 4652234 ×2
  • Technic Axle and Pin Connector Perpendicular Triple Light Bluish Gray Part 63869 Element 6331441 or 4538007 ×7
  • Technic Beam 3 x 5 Thick [90° Offset Centre Beam Holes] Light Bluish Gray Part 14720 Element 6055519 ×2
  • Technic Bush Light Bluish Gray Part 3713 Element 6275844 or 6271817 1 spare in the box ×10
  • Technic Bush 1/2 Smooth with Axle Hole Semi-Reduced Light Bluish Gray Part 32123b Element 6271165 or 4211573 1 spare in the box ×10
  • Technic Pin 1/2 without Friction Ridges Light Bluish Gray Part 4274 Element 4274194 or 4211483 1 spare in the box ×10
  • Technic Pin Connector Hub Perpendicular 3 x 3 Bent with 4 Pins (Pin Ridges Along Part) Light Bluish Gray Part 49130 Element 6313453 ×4
  • Technic Pin Connector Hub Perpendicular 3L with 4 Pins (Squared Holes) Light Bluish Gray Part 65489 Element 6282158 ×12
  • Technic Pin Connector Hub with 2 Pins with Friction Ridges Lengthwise [Small Squared Pin Holes] Light Bluish Gray Part 44874 Element 6321303 ×4
  • Technic Pin Double with Axle Hole - Squared Holes Light Bluish Gray Part 65098 Element 6406084 or 6315900 ×4
  • Technic Pin Long with Friction Ridges Lengthwise and Stop Bush [3 Lateral Holes, Big Pin Hole] Light Bluish Gray Part 32054 Element 4211865 ×12
  • Technic Pin without Friction Ridges Lengthwise Light Bluish Gray Part 3673 Element 4211807 or 3673194 1 spare in the box ×18
  • Technic Turntable Large Type 3 Base Light Bluish Gray Part 18939 Element 6109285 ×1
  • Technic Turntable Small Top Light Bluish Gray Part 99009 Element 4652235 ×2

White 105 pieces

  • Cable, USB, SPIKE / Mindstorms Robot Inventor White Part 39881 Element 6322774 or 6277572 ×1
  • Dish 6 x 6 Inverted (Radar) with Solid Studs White Part 44375b Element 4514791 ×1
  • Rubber Belt Small [15mm ID] [Round Cross Section] White Part 85543 Element 6699001 or 4580665 ×2
  • Sensor, Color, SPIKE White Part 37308 Element 6217705 ×1
  • Sensor, Distance, SPIKE White Part 37316 Element 6302968 or 6217717 ×1
  • Technic Axle Connector Smooth [with x Hole + Orientation] White Part 59443 Element 6212049 ×8
  • Technic Axle and Pin Connector Angled #1 White Part 32013 Element 6332573 or 4118981 ×5
  • Technic Axle and Pin Connector Angled #2 - 180° White Part 32034 Element 6271870 or 4125554 ×1
  • Technic Axle and Pin Connector Angled #4 - 135° White Part 32192 Element 6262904 or 6137758 ×6
  • Technic Axle and Pin Connector Angled #5 - 112.5° White Part 32015 Element 6271349 or 6003297 ×2
  • Technic Beam 1 x 13 Thick White Part 41239 Element 6634561 or 4620671 ×5
  • Technic Beam 1 x 2 Thick with Pin Hole and Axle Hole White Part 60483 Element 6265135 or 6177268 ×3
  • Technic Beam 1 x 3 Thick White Part 32523 Element 6632140 or 4208160 ×2
  • Technic Beam 1 x 7 Thick White Part 32524 Element 6564912 or 6318056 ×1
  • Technic Driving Ring Connector White Part 18948 Element 6276052 or 6100932 ×1
  • Technic Panel 3 x 11 x 1 White Part 15458 Element 6055627 ×2
  • Technic Panel 5 x 11 x 1 White Part 64782 Element 6004135 or 4580019 ×4
  • Technic Panel Car Mudguard 15 x 2 x 7 White Part 46882 Element 6295159 ×2
  • Technic Panel Curved 11 x 3 with 2 Pin Holes through Panel Surface White Part 62531 Element 6004137 ×3
  • Technic Panel Curved 7 x 3 with 2 Pin Holes through Panel Surface White Part 24119 Element 6246996 ×2
  • Technic Panel Curved and Bent 6 x 3 White Part 24116 Element 6268001 or 6133244 ×2
  • Technic Panel Fairing # 3 Small Smooth Long, Side A White Part 64683 Element 4547581 ×2
  • Technic Panel Fairing # 4 Small Smooth Long, Side B White Part 64391 Element 4547582 ×2
  • Technic Panel Fairing #1 Small Smooth Short, Side A White Part 87080 Element 4558878 ×2
  • Technic Panel Fairing #2 Small Smooth Short, Side B White Part 87086 Element 4558874 ×2
  • Technic Panel Fairing #21 5L Small Smooth, Side B White Part 11946 Element 6330084 or 6114580 ×2
  • Technic Panel Fairing #22 5L Small Smooth, Side A White Part 11947 Element 6343987 or 6114583 ×2
  • Technic Panel Fairing #5 Long Smooth, Side A White Part 64681 Element 4558802 ×3
  • Technic Panel Fairing #6 Long Smooth, Side B White Part 64393 Element 4558797 ×3
  • Technic Pin Connector Hub with 1 Pin with Friction Ridges Lengthwise [Centered Friction Ridge] White Part 65487 Element 6282148 ×18
  • Technic Pin Connector Round 1L [Beam] White Part 18654 Element 6550155 or 6177114 1 spare in the box ×10
  • Wheel 18 x 8 with Fake Bolts and Shallow Spokes and Axle Hole White Part 56903 Element 6013484 ×4

Dark Turquoise 97 pieces

  • Battery Pack, Rechargeable, Mindstorms Robot Inventor Dark Turquoise Part 67704 Element 6413277 or 6299315 ×1
  • Dish 8 x 8 Inverted [Radar], Solid Studs, Rounded Anti-stud Underside Dark Turquoise Part 3961 ×1
  • Hub, Programmable, Mindstorms Robot Inventor Dark Turquoise Part 67718 Element 6413266 or 6299573 ×1
  • Technic Axle and Pin Connector Perpendicular Dark Turquoise Part 6536 Element 6295183 or 4173663 ×8
  • Technic Axle and Pin Connector Perpendicular 3L with 2 Pin Holes Dark Turquoise Part 42003 Element 6295182 ×4
  • Technic Ball Joint Dark Turquoise Part 32474 Element 6295155 or 6231378 ×2
  • Technic Base Frame 11 x 19 Dark Turquoise Part 39369 Element 6252639 ×1
  • Technic Beam 1 x 3 Thick Dark Turquoise Part 32523 Element 6596991 or 6295145 ×8
  • Technic Beam 1 x 5 Thick Dark Turquoise Part 32316 Element 6533555 or 6295144 ×9
  • Technic Beam 1 x 9 Thick Dark Turquoise Part 40490 Element 6584234 or 6314820 ×14
  • Technic Beam 2 x 4 L-Shape Thick Dark Turquoise Part 32140 Element 6509369 or 6298570 ×6
  • Technic Beam 3 x 3 T-Shape Thick Dark Turquoise Part 60484 Element 6295232 ×6
  • Technic Beam 3 x 5 L-Shape Thick Dark Turquoise Part 32526 Element 6295146 ×6
  • Technic Connector Beam 3 x 3 Dark Turquoise Part 39793 Element 6252655 ×9
  • Technic Pin Connector Round 1L [Beam] Dark Turquoise Part 18654 Element 6295149 1 spare in the box ×10
  • Tile 1 x 2 with Groove Dark Turquoise Part 3069b Element 6213779 or 4164140 ×2
  • Tile 2 x 4 with Groove Dark Turquoise Part 87079 Element 6223065 ×1
  • Wire Clip with Axle Hole Dark Turquoise Part 49283 Element 6295401 ×8

Dark Bluish Gray 32 pieces

  • Launcher, Brick Special 2 x 6 Spring Shooter with Light Bluish Gray Top Dark Bluish Gray Part 49743c01 Element 6296378 ×2
  • Technic Axle 4 with Stop Dark Bluish Gray Part 87083 Element 6083620 or 4560177 ×6
  • Technic Axle 5.5 with Stop [Rounded Short End] Dark Bluish Gray Part 59426 Element 4508553 ×2
  • Technic Axle 8 with Stop Dark Bluish Gray Part 55013 Element 4499858 ×4
  • Technic Axle Pin 3L with Friction Ridges Lengthwise and 1L Axle Dark Bluish Gray Part 11214 Element 6015356 ×14
  • Technic Gear 24 Tooth [New Style with Single Axle Hole] Dark Bluish Gray Part 3648b Element 6133119 or 4514558 ×2
  • Technic Gear 8 Tooth [Reinforced] Dark Bluish Gray Part 10928 Element 6631413 or 6012451 ×2

Tan 24 pieces

  • Technic Axle 4 with Centre Stop Tan Part 99008 Element 4666999 ×2
  • Technic Axle Pin without Friction Ridges Lengthwise Tan Part 3749 Element 4666579 or 4186017 ×6
  • Technic Gear 12 Tooth Bevel Tan Part 6589 Element 4565452 or 4514556 ×6
  • Technic Gear 20 Tooth Double Bevel with Axle Hole Type 1 [+ Opening] Tan Part 18575 Element 6346517 or 6084724 ×4
  • Technic Pin Long without Friction Ridges Tan Part 32556 ×6

Red 23 pieces

  • Ball, Hard Plastic, 51mm (approx. 6 studs diameter) Red Part 41250 Element 4156530 ×1
  • Differential Gear - 28 Tooth with Round Axle Hole Red Part 65413 Element 6285646 ×1
  • Projectile, Large Figure Weapon, Zamor Sphere / Ball Red Part 54821 Element 4545430 ×1
  • Technic Axle 2 Notched Red Part 32062 Element 4142865 ×10
  • Technic Axle 6 Red Part 3706 Element 6130002 or 4191526 ×2
  • Technic Beam 1 x 3 Thick Red Part 32523 Element 4153718 ×2
  • Technic Pin Long with Friction Ridges Lengthwise and Stop Bush [3 Lateral Holes, Big Pin Hole] Red Part 32054 Element 4140806 or 4125198 ×6

Reddish Brown 14 pieces

  • Technic Axle 3 with Stop Reddish Brown Part 24316 Element 6135494 ×12
  • Technic Axle 5 with Stop Reddish Brown Part 15462 Element 6159763 ×2

Yellow 8 pieces

  • Technic Axle 5 Yellow Part 32073 Element 6130008 ×4
  • Technic Axle 9 Yellow Part 60485 Element 6130010 ×2
  • Technic Beam 1 x 3 Thick Yellow Part 32523 Element 4153707 ×2

Green 2 pieces

  • Technic Beam 1 x 3 Thick Green Part 32523 Element 6007973 or 4158868 ×2

[No Color/Any Color] 1 piece

  • Sticker Sheet for Set 51515-1 [No Color/Any Color] Part 73229 Element 6327015 ×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.