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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.

McLaren P1

Checking

42172 McLaren P1

3,893 pieces in 374 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.

Every bag and the box. Shake out each bag, check its corners and seams, and look inside the empty box.
Inside what you have built. Small pieces lodge inside tubes, under plates and between studs. Turn the model over and look.
The last few steps. Compare each recent step with its parts callout. A piece used in the wrong place earlier leaves you one short later.
Look-alike colors. 15 parts in this set come in two colors that are easy to mix up; they are listed below.
The spare pieces. This set comes with 50 spare pieces, marked on each row of the checklist. One may be the piece you need.
The floor and your building area. Check under furniture, the chair and the edges of your building surface.

Look-alike colors in this set

These parts appear in this set in two colors that are easy to confuse. If you are one short in one color, check whether it went in where the other color belongs. Each color has its own element ID in the parts list at the back of the instructions.

Plate 1 x 1 Black ×2 Dark Bluish Gray ×2 Black is darker than Dark Bluish Gray.
Technic Axle and Pin Connector Angled #1 Black ×31 Dark Bluish Gray ×4 Black is darker than Dark Bluish Gray.
Technic Axle and Pin Connector Angled #4 - 135° Black ×4 Dark Bluish Gray ×3 Black is darker than Dark Bluish Gray.
Technic Axle and Pin Connector Perpendicular Black ×36 Dark Bluish Gray ×10 Black is darker than Dark Bluish Gray.
Technic Axle and Pin Connector Perpendicular Double Split [Reinforced] Black ×3 Dark Bluish Gray ×4 Black is darker than Dark Bluish Gray.
Technic Beam 1 x 13 Thick Black ×16 Dark Bluish Gray ×3 Black is darker than Dark Bluish Gray.

9 more look-alike pairs

Technic Beam 1 x 15 Thick with Alternating Holes Black ×1 Dark Bluish Gray ×6 Black is darker than Dark Bluish Gray.
Technic Beam 1 x 3 Thick Black ×20 Dark Bluish Gray ×5 Black is darker than Dark Bluish Gray.
Technic Beam 1 x 3 Thin Black ×22 Dark Bluish Gray ×14 Black is darker than Dark Bluish Gray.
Technic Beam 1 x 5 Thick Black ×25 Dark Bluish Gray ×4 Black is darker than Dark Bluish Gray.
Technic Beam 1 x 7 Thick with Alternating Holes Black ×10 Dark Bluish Gray ×9 Black is darker than Dark Bluish Gray.
Technic Beam 1 x 9 Thick Black ×13 Dark Bluish Gray ×7 Black is darker than Dark Bluish Gray.
Technic Beam 2 x 4 L-Shape Thick Black ×19 Dark Bluish Gray ×27 Black is darker than Dark Bluish Gray.
Technic Driving Ring Connector Smooth [2 rounded and 2 flat side walls] Black ×5 Dark Bluish Gray ×1 Black is darker than Dark Bluish Gray.
Technic Pin Connector Round 1L [Beam] Black ×20 Dark Bluish Gray ×2 Black is darker than Dark Bluish Gray.

Piece checklist

Technic Bushes 62 pieces

Technic Bush Black Part 3713 Element 6332148 or 6210506 1 spare in the box ×5
Technic Bush 1/2 Smooth with Axle Hole Semi-Reduced Light Bluish Gray Part 32123b Element 6271165 or 4211573 2 spares in the box ×16
Technic Bush Red Part 3713 Element 6271820 or 4227155 3 spares in the box ×20
Technic Bush 1/2 Smooth with Axle Hole Semi-Reduced Yellow Part 32123b Element 6271167 or 3212324 2 spares in the box ×21

Bricks Sloped 30 pieces

Brick Sloped 18° 2 x 1 x 2/3 with 4 Slots / Grate Black Part 61409 Element 4541191 ×8
Brick Sloped 30° 1 x 2 x 2/3 Black Part 85984 Element 4548180 ×3
Brick Sloped 1 x 6 x 1 with 1 x 2 x 1/3 Cutout Bright Light Orange Part 4569 Element 6478029 ×2
Brick Sloped 45° 2 x 1 with 2/3 Inverted Cutout and no stud Dark Bluish Gray Part 28192 Element 6168776 ×2
Brick Sloped 30° 1 x 1 x 2/3 (Cheese Slope) Metallic Gold Part 54200 Element 6546111 or 6191668 1 spare in the box ×12
Brick Sloped 30° 1 x 1 x 2/3 (Cheese Slope) Trans-Red Part 54200 Element 6245252 or 4244363 1 spare in the box ×3

Tiles Round and Curved 18 pieces

Tile Round 1 x 1 Quarter Black Part 25269 Element 6172383 1 spare in the box ×1
Tile Round 1 x 1 with Silver McLaren Logo Print Black Part 98138pr0416 Element 6463320 1 spare in the box ×4
Tile Round 2 x 2 with Silver McLaren Logo Print Black Part 14769pr1314 Element 6463313 ×1
Tile Round 1 x 1 Light Bluish Gray Part 98138 Element 6284071 or 4650260 1 spare in the box ×3
Tile Round 1 x 1 Quarter Metallic Gold Part 25269 Element 6546116 or 6251591 1 spare in the box ×4
Tile Round 1 x 1 Trans-Clear Part 98138 Element 6514191 or 6274738 1 spare in the box ×4
Tile Round 1 x 1 Yellow Part 98138 Element 6284577 or 6070714 1 spare in the box ×1

Bricks Curved 16 pieces

Brick Curved 4 x 1 No Studs [Stud Holder with Symmetric Ridges] Black Part 11153 Element 6580394 or 6037746 ×4
Brick Curved 4 x 2 No Studs Black Part 93606 Element 4647286 ×2
Brick Curved 3 x 1 No Studs Bright Light Orange Part 50950 Element 6022064 ×6
Brick Curved 4 x 1 Double, No Studs with Black 'McLaren' Print Bright Light Orange Part 93273pr9989 Element 6463319 ×4

Plates Special 15 pieces

Plate Special 1 x 2 Side Handle [Free Ends] Black Part 2540 Element 4140588 or 254026 ×4
Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper) Black Part 15573 Element 6092585 ×1
Plate Special 1 x 2 with Pin Hole Underneath Black Part 18677 Element 6192309 or 6167497 ×2
Plate Special 2 x 2 with 1 Pin Hole [Complete Underside Rib] Black Part 10247 Element 6061032 ×2
Plate Special Round 1 x 1 with Hollow Stud and Horizontal Bar 1L Black Part 32828 Element 6196548 1 spare in the box ×2
Plate Special 1 x 2 with Pin Hole Underneath Light Bluish Gray Part 18677 Element 6168633 or 6089147 ×2
Plate Special 1 x 1 with Clip Light, Bar Hole [Thick Ring] White Part 4081b Element 6281990 or 4632566 ×2

Bricks Round and Cones 12 pieces

Brick Round Corner, Curved 3 x 3 x 1 Quarter Circle Black Part 76797 Element 6385597 ×2
Brick Round 1 x 1 diameter Tube with 90 Degree Elbow (2 x 2 x 1) and Axle Holes (Crossholes) at each end Pearl Titanium Part 25214 Element 6156875 ×10

Tiles 11 pieces

Tile 1 x 1 with Groove Black Part 3070b Element 307026 1 spare in the box ×2
Tile 1 x 4 with Groove Black Part 2431 Element 243126 ×1
Tile 2 x 2 with Groove Black Part 3068b Element 306826 ×1
Tile 2 x 3 with Silver Border, White '14:23', Cut Squares Print Black Part 26603pr0141 Element 6463312 ×1
Tile 2 x 4 with Groove Black Part 87079 Element 4560182 ×2
Tile 8 x 16 with White/Light Bluish Grey McLaren Stats Print Black Part 90498pr0028 Element 6463322 ×1
Tile 1 x 2 with Groove Dark Bluish Gray Part 3069b Element 4211052 ×1
Tile 1 x 3 with Coloured Speedometer and Gauges Print Dark Bluish Gray Part 63864pr0054 Element 6463314 ×1
Tile 1 x 4 with P1 Symbol, Code Print White Part 2431pr0221 Element 6521103 or 6503810 ×1

Tubes and Hoses 11 pieces

Axle Hose, Soft 7L Black Part 32580 Element 6132744 ×2
Axle Hose, Soft 19L Bright Light Orange Part 32235 Element 6476804 or 6172361 ×3
Axle Hose, Soft 12L Red Part 32200 Element 6296597 or 6097866 ×2
Axle Hose, Soft 7L Red Part 32580 Element 6334708 or 4569751 ×2
Axle Hose, Soft 7L White Part 32580 Element 6212046 ×2

Technic Bricks 10 pieces

Technic Brick 1 x 1 with Axle Hole Black Part 73230 Element 6344819 ×2
Technic Brick 1 x 2 [2 Pin Holes] Black Part 32000 Element 3200026 ×2
Technic Brick 1 x 2 with Axle Hole Type 1 [+ Opening] and Bottom Pin Black Part 32064a Element 6178922 or 4233487 ×3
Technic Brick 1 x 6 [5 Pin Holes] Black Part 3894 Element 389426 ×1
Technic Pin Connector Block 1 x 5 x 3 Black Part 32333 Element 6271358 or 4141810 ×2

Plates Round Curved and Dishes 9 pieces

Plate Round 1 x 1 with Solid Stud Black Part 6141 Element 614126 1 spare in the box ×4
Plate Round 2 x 2 with Axle Hole Type 1 (+ Opening) Black Part 4032a Element 403226 ×1
Plate Round 1 x 1 with Open Stud Light Bluish Gray Part 85861 Element 6168647 or 6124825 1 spare in the box ×4

Bars, Ladders and Fences 8 pieces

Bar 1L with Clip [Cut Edges and One Side Hole] [Full Clip] White Part 3484 Element 6439046 ×4
Bar 4L (Lightsaber Blade / Wand) White Part 30374 Element 6116602 or 4129836 ×4

Minifig Upper Body 8 pieces

Arm Skeleton [Bent / 2 Clips] Dark Bluish Gray Part 93609 Element 6318697 or 6167900 ×8

Wheels and Tyres 8 pieces

Tyre 87.9 x 44 Low Black Part 80279 Element 6362559 ×4
Wheel 75 x 41 McLaren P1 Pearl Titanium Part 5428 Element 6470764 ×4

Technic Special 6 pieces

Technic Tooth 1 x 3 with Axle Hole [Hollow Underside] Black Part 48267 Element 6288220 ×2
Technic Changeover Catch - New Style Red Part 51149 Element 6313493 ×2
Technic Tooth 1 x 3 with Axle Hole [Hollow Underside] Trans-Red Part 48267 Element 6514318 or 6275769 ×2

String, Bands and Reels 5 pieces

Technic Rubber Belt Medium [24mm ID] [Round Cross Section] Red Part 85544 Element 4544145 or 4544143 ×1
Rubber Belt Small [15mm ID] [Round Cross Section] White Part 85543 Element 6699001 or 4580665 ×4

Large Buildable Figures 3 pieces

Large Figure Weapon, Barrel with 2 Pin Holes and 3 Axle Holes Light Bluish Gray Part 98585 Element 6186129 or 6039505 ×3

Animal / Creature Body Parts 2 pieces

Animal Body Part, Barb / Claw / Tooth / Talon / Horn, Medium White Part 87747 Element 6270092 or 4613941 ×2

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.