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.

MASTERPIECE Challenge Kit

Checking

45823 MASTERPIECE Challenge Kit

1,685 pieces in 442 part and color combinations, plus 21 minifigures.

The official piece count includes the 71 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.

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. 2 parts in this set come in two colors that are easy to mix up; they are listed below.
The spare pieces. Many sets include a few extra small pieces. Check them before you order a replacement.
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.

Technic Beam 1 x 7 Thick Dark Turquoise ×1 Medium Azure ×1 Dark Turquoise is darker than Medium Azure.
Technic Beam 1 x 3 Thick Black ×1 Dark Bluish Gray ×2 Black is darker than Dark Bluish Gray.

Piece checklist

Tiles Round and Curved 57 pieces

Tile Round 2 x 2 with Bottom Stud Holder Blue Part 14769 Element 6133844 ×2
Tile Round 1 x 1 Dark Pink Part 98138 Element 6322821 ×8
Tile Round 1 x 1 Lavender Part 98138 Element 6322820 ×1
Tile Round 1 x 1 Quarter Medium Lavender Part 25269 Element 6199893 ×12
Tile 2 x 2 Curved, Macaroni White Part 27925 Element 6550162 or 6172674 ×4
Tile 3 x 3 Curved, Macaroni White Part 79393 Element 6564909 or 6373439 ×4
Tile Round 1 x 1 Half Circle White Part 24246 Element 6609539 or 6250591 ×5
Tile Round 1 x 1 Quarter White Part 25269 Element 6548285 or 6172366 ×19
Tile Round 1 x 1 with Squinted Eye, Center Side Pupil Print White Part 98138pr0083 Element 6329648 ×2

Technic Bricks 30 pieces

Technic Brick 1 x 2 [1 Pin Hole] Black Part 3700 Element 370026 ×10
Technic Brick 1 x 2 with Axle Hole Type 1 [+ Opening] and Bottom Pin Black Part 32064a Element 6178922 or 4233487 ×2
Technic Brick 1 x 2 [1 Pin Hole] Blue Part 3700 Element 370023 ×2
Technic Brick 1 x 2 with Axle Hole Type 1 [+ Opening] and Bottom Pin Green Part 32064a Element 6206248 or 4233489 ×2
Technic Brick 1 x 2 [1 Pin Hole] White Part 3700 Element 6619284 or 370001 ×10
Technic Brick 1 x 2 [2 Pin Holes] White Part 32000 Element 6564911 or 3200001 ×2
Technic Brick 1 x 2 with Axle Hole Type 1 [+ Opening] and Bottom Pin White Part 32064a Element 6548286 or 6178921 ×2

Technic Bushes 23 pieces

Technic Bush Black Part 3713 Element 6332148 or 6210506 ×2
Technic Bush Light Bluish Gray Part 3713 Element 6275844 or 6271817 ×11
Technic Bush Red Part 3713 Element 6271820 or 4227155 ×2
Technic Bush 1/2 Smooth with Axle Hole Semi-Reduced Yellow Part 32123b Element 6271167 or 3212324 ×8

Wheels and Tyres 21 pieces

Technic Wedge Belt Wheel [aka Pulley] Black Part 4185 Element 6323668 or 6192130 ×3
Tyre 24 x 14 Shallow Tread (Tread Small Hub), Band Around Center of Tread Black Part 89201 Element 6132299 or 4639695 ×7
Wheel 18 x 14 with Pin Hole, Fake Bolts and Shallow Spokes Black Part 55981 Element 6359824 or 6109682 ×3
Wheel 18mm x 14mm with Axle Hole, Fake Bolts and Shallow Spokes Black Part 55982 Element 4517737 ×4
Wheel Skateboard / Trolley Black Part 2496 Element 6223673 or 4569104 ×2
Wheel Roller Coaster Dark Bluish Gray Part 24869 Element 6135290 ×2

Technic Gears 20 pieces

Technic Gear 12 Tooth Double Bevel Black Part 32270 Element 4177431 ×7
Technic Gear 36 Tooth Double Bevel Black Part 32498 Element 4255563 or 4177434 ×1
Technic Gear 8 Tooth [Reinforced] Dark Bluish Gray Part 10928 Element 6631413 or 6012451 ×1
Technic Gear 16 Tooth Reinforced [New Style] Light Bluish Gray Part 94925 Element 4640536 ×1
Technic Gear 28 Tooth Double Bevel Light Bluish Gray Part 46372 Element 6259270 ×2
Technic Worm Gear 6M with Axle Hole Light Bluish Gray Part 73763 Element 6417811 ×5
Technic Worm Gear Type 2 Light Bluish Gray Part 32905 Element 6185471 ×1
Technic Gear 20 Tooth Double Bevel with Axle Hole Type 1 [+ Opening] Tan Part 18575 Element 6346517 or 6084724 ×1
Technic Knob Wheel Yellow Part 32072 Element 6284189 or 4203493 ×1

Technic Special 17 pieces

Technic Brick Special 2 x 2 with Pin Hole, Rotation Joint Ball Half [Vertical Side] Black Part 48171 Element 6302828 or 6187578 ×2
Technic Ball Joint Bright Light Orange Part 32474 Element 6071608 ×1
Technic Tooth 1 x 3 with Axle Hole [Hollow Underside] Bright Pink Part 48267 Element 6395623 ×1
Technic Ball Joint Dark Azure Part 32474 Element 6412745 ×1
Technic Ball Joint Dark Pink Part 32474 Element 6228091 ×1
Bar, Ring 7L Diameter, with 2 Axle Connectors Orange Part 79851 Element 6444697 ×6
Technic Tooth 1 x 3 with Axle Hole [Hollow Underside] Red Part 48267 Element 6285599 ×1
Technic Ball Joint White Part 32474 Element 6052864 or 4585627 ×1
Technic Tooth 1 x 3 with Axle Hole [Hollow Underside] White Part 48267 Element 6288218 ×3

Technic Beams Special 13 pieces

Technic Beam 3 x 0.5 Liftarm with Boss and Blocked, Squared Pin Hole Black Part 61408 Element 6313520 ×1
Technic Beam Frame 11 x 15 Black Part 39790 Element 6295161 ×1
Technic Beam Frame 7 x 11 Magenta Part 39794 Element 6252663 ×1
Technic Beam Frame 5 x 7 with 3 x 5 Opening Thick White Part 64179 Element 6632145 or 6016156 ×7
Technic Beam Frame 7 x 11 White Part 39794 Element 6247435 ×3

Bricks Special 12 pieces

Brick Special 2 x 2 x 1 2/3 with Worm Gear Hole Black Part 73764 Element 6417813 ×1
Brick Special 1 x 1 with Stud on 1 Side Blue Part 87087 Element 4583862 ×1
Brick Special 1 x 1 with Headlight Bright Green Part 4070 Element 6314376 ×2
Brick Special 1 x 2 x 1 2/3 with 4 Studs on 1 Side Bright Pink Part 22885 Element 6403266 or 6273397 ×1
Brick Special 1 x 1 with Stud on 1 Side Dark Blue Part 87087 Element 6554212 or 6224377 ×1
Brick Special 1 x 1 with Headlight Dark Bluish Gray Part 4070 Element 4211044 ×1
Brick Special 1 x 2 x 1 2/3 with 4 Studs on 1 Side Dark Pink Part 22885 Element 6132426 ×1
Brick Special 1 x 2 Palisade [aka Log] White Part 30136 Element 6552148 or 6059185 ×2
Brick Special 1 x 2 with Grille White Part 2877 Element 6552093 or 287701 ×2

Hinges, Arms and Turntables 12 pieces

Turntable 2 x 2 Plate, Base Black Part 3680 Element 368076 or 368026 ×1
Hinge Plate 1 x 4 Swivel Top / Base - Hollow Clip [Complete Assembly] Light Bluish Gray Part 1927 Element 6416524 ×3
Turntable 2 x 2 Plate - Top Light Bluish Gray Part 3679 Element 4540203 or 4495467 ×2
Hinge Brick 1 x 2 Base White Part 3937 Element 6619287 or 393701 ×2
Hinge Brick 2 x 2 Top Plate Thin White Part 6134 Element 6548272 or 4612342 ×2
Turntable 2 x 2 Plate, Base White Part 3680 Element 368001 ×1
Turntable 4 x 4 Square Base, Locking White Part 61485 Element 6619301 or 4611927 ×1

Tiles Special 11 pieces

Tile Special 1 x 2 Grille with Bottom Groove Lime Part 2412b Element 6263442 or 4537921 ×1
Tile Special 1 x 1 with Clip with Rounded Edges Red Part 15712 Element 6348058 or 6072998 ×2
Tile Special 1 x 2 Grille with Bottom Groove Sand Green Part 2412b Element 6223126 or 4163471 ×1
Tile Special 2 x 2 Inverted White Part 11203 Element 6564913 or 6013866 ×6
Tile Special Round 2 x 2 with Hole White Part 15535 Element 6310185 ×1

Plants & Trees 9 pieces

Plant, Flower, Plate Round 1 x 1 with 5 Petals Bright Green Part 24866 Element 6526150 or 6206150 ×1
Plant, Plate 1 x 1 Round with 3 Leaves Bright Light Blue Part 32607 Element 6420914 ×1
Plant, Flower, Minifig Accessory with 7 Thick Petals and Pin Dark Pink Part 32606 Element 6206151 ×1
Plant, Plate 1 x 1 Round with 3 Leaves Dark Turquoise Part 32607 Element 6270179 ×1
Plant / Creature Body Part, Vine / Tail / Tentacle / Bionicle Spine, Spiky Green Part 55236 Element 6270055 or 6154865 ×2
Plant, Leaves 4 x 3 Green Part 2423 Element 6268814 or 242328 ×1
Plant, Leaves 4 x 3 Lime Part 2423 Element 6268818 or 6094069 ×1
Plant, Flower, Plate Round 1 x 1 with 5 Petals Yellow Part 24866 Element 6299813 ×1

Bricks Wedged 7 pieces

Brick Wedged, Curved 2 x 1 with Stud Notch Left Black Part 29120 Element 6181720 ×1
Brick Wedged, Curved 2 x 1 with Stud Notch Right Black Part 29119 Element 6181713 ×1
Brick Wedged, Curved 4 x 3 No Studs [Plain] Lime Part 64225 Element 6023954 ×1
Brick Wedged, Curved Triple 4 x 4 x 2/3, 2 Studs with Magenta 'MASTERPIECE' Print White Part 45677pr0023 Element 6451559 ×4

Minifig Accessories 7 pieces

Equipment Laptop Black Part 62698 Element 6087083 or 4527063 ×1
Equipment Magnifying Glass with Thick Frame, Hollow Handle, Trans-Clear Lens Pattern Black Part 38648pat0001 Element 6499140 or 6325525 ×1
Sports Skateboard with Trolley Wheel Holders Dark Purple Part 42511 Element 6174272 or 6030185 ×1
Equipment Pen with Tip and Cap Dark Purple Print Light Aqua Part 35809pat0001 Element 6213681 ×1
Musical Instrument Microphone [Plain] Magenta Part 90370 Element 6257777 ×1
Tap 1 x 1 without Hole in Spout White Part 4599b Element 459901 ×2

Rock 6 pieces

Rock 1 x 1 Jewel / Gem 24 Facet Trans-Bright Green Part 30153 Element 6513978 or 6247800 ×1
Rock 1 x 1 Jewel / Gem 24 Facet Trans-Dark Blue Part 30153 Element 6513973 or 6247793 ×1
Rock 1 x 1 Jewel / Gem 24 Facet Trans-Green Part 30153 Element 6513970 or 6247788 ×1
Rock 1 x 1 Jewel / Gem 24 Facet Trans-Light Blue Part 30153 Element 6513972 or 6247792 ×1
Rock 1 x 1 Jewel / Gem 24 Facet Trans-Red Part 30153 Element 6513969 or 6247785 ×1
Rock 1 x 1 Jewel / Gem 24 Facet Trans-Yellow Part 30153 Element 6513974 or 6247795 ×1

Transportation - Land 6 pieces

Vehicle Track, Roller Coaster Ramp Small, 3 Bricks Elevation Light Bluish Gray Part 34738 Element 6224370 ×2
Vehicle Track, Roller Coaster Straight 16L Light Bluish Gray Part 25059 Element 6185380 ×3
Vehicle Base, Roller Coaster Car 4 x 5 Medium Azure Part 26021 Element 6261518 ×1

Technic Steering, Suspension and Engine 5 pieces

Technic Shock Absorber 11L with Internal Spring, Black Top Black Part 65151c02 Element 6410048 ×1
Technic Link 1 x 6 without Stoppers Dark Bluish Gray Part 32005a Element 4629920 or 4211026 ×4

Bars, Ladders and Fences 4 pieces

Bar 3L Black Part 87994 Element 6185316 or 6093525 ×1
Bar 8L - Two Stop Rings / One Pin, Technic Figure Ski Pole [Flat End] Black Part 2714b Element 6361933 or 6278257 ×2
Fence Decorative 3 x 3 x 2 Quarter Round with 2 Studs White Part 41823 Element 6426061 ×1

Large Buildable Figures 3 pieces

Large Figure Weapon, Barrel with 2 Pin Holes and 3 Axle Holes Black Part 98585 Element 6186133 or 6156897 ×3

Animals / Creatures 2 pieces

Animal, Frog Bright Pink Part 33320 Element 6327825 ×1
Animal, Frog Coral Part 33320 Element 6399743 ×1

Plates Wedged 2 pieces

Wedge Plate 2 x 4 White Part 51739 Element 6552128 or 4249506 ×2

Windows and Doors 2 pieces

Window 1 x 2 x 2 2/3 with Rounded Top White Part 30044 Element 6619297 or 4247139 ×2

Animal / Creature Body Parts 1 piece

Animal Body Part, Horn (Cattle) / Tentacle / Vine / Branch / Tongue - Long Dark Bluish Gray Part 13564 Element 6269080 or 6192145 ×1

Energy Effects 1 piece

Wave / Flame Rounded with Base Rim Trans-Orange Part 6126b Element 6167741 or 4261397 ×1

Minifig Headwear 1 piece

Crown / Flower / Egg Shell Half Pearl Gold Part 39262 Element 6257048 ×1

Minifig Shields, Weapons, & Tools 1 piece

Weapon Chakram / Hoop Blade / Ring Black Part 35485 Element 6391688 ×1

Panels 1 piece

Panel 1 x 6 x 5 Trans-Clear Part 59349 Element 6514106 or 6245253 ×1

String, Bands and Reels 1 piece

String with End Studs 41L Overall Black Part 14226c41 Element 6096957 or 6074034 ×1

Tools 1 piece

Brick and Axle Separator v2.0 Dark Turquoise Part 96874 Element 6254100 ×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.