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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.

The Modern Treehouse

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21174 The Modern Treehouse

894 pieces in 185 part and color combinations, plus 4 minifigures.

The official piece count includes the 15 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.

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.

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Piece checklist

Green 166 pieces

  • Brick 1 x 10 Green Part 6111 Element 6249998 or 4529156 ×6
  • Brick 2 x 4 Green Part 3001 Element 4106356 or 300128 ×28
  • Plant, Flower, Plate Round 1 x 1 with 5 Petals Green Part 24866 Element 6135287 ×2
  • Plate 1 x 1 Green Part 3024 Element 302428 ×4
  • Plate 1 x 2 Green Part 3023 Element 302328 ×15
  • Plate 1 x 4 Green Part 3710 Element 371028 ×2
  • Plate 2 x 10 Green Part 3832 Element 383228 ×2
  • Plate 2 x 2 Green Part 3022 Element 302228 ×43
  • Plate 2 x 2 Corner Green Part 2420 Element 4157120 or 242028 ×12
  • Plate 2 x 4 Green Part 3020 Element 302028 ×22
  • Plate 2 x 8 Green Part 3034 Element 303428 ×2
  • Plate 4 x 6 Green Part 3032 Element 4116671 ×7
  • Plate 6 x 12 Green Part 3028 Element 6177783 or 4614769 ×1
  • Plate Special 1 x 2 [Side Handle Closed Ends] Green Part 48336 Element 4521931 ×3
  • Plate Special 1 x 2 with Clips Horizontal [Open O Clips] Green Part 60470b Element 6347288 or 4556159 ×3
  • Technic Beam 1 x 9 Thick Green Part 40490 Element 6115618 or 6036624 ×2
  • Tile 2 x 4 with Groove Green Part 87079 Element 4566179 ×12

White 153 pieces

  • Animal Body Part, Bird, Chicken 1 x 1 with Cube Head with Face Print White Part 35750pr0001 Element 6545610 or 6217227 ×2
  • Bracket 1 x 2 - 1 x 2 Inverted White Part 99780 Element 6548278 or 6070698 ×2
  • Bracket 1 x 2 - 2 x 2 Inverted White Part 99207 Element 6552151 or 6548279 ×1
  • Brick 1 x 2 White Part 3004 Element 6548257 or 4613964 ×14
  • Brick 1 x 2 with Black 'TNT' Pixelated Print White Part 3004pr0036 Element 6097028 ×2
  • Brick 1 x 4 White Part 3010 Element 6550135 or 301001 ×6
  • Brick 1 x 6 White Part 3009 Element 6552097 or 6548259 ×2
  • Brick 2 x 2 White Part 3003 Element 6552095 or 6548256 ×31
  • Brick 2 x 8 White Part 3007 Element 6619309 or 6033776 ×13
  • Brick Special 1 x 1 Studs on 4 Sides White Part 4733 Element 4111971 or 473301 ×2
  • Food Egg with 1.5mm Hole [Plain] White Part 24946 Element 6550158 or 6143595 ×1
  • Minifig Neckwear Bracket [One Stud] - Reinforced White Part 28974 Element 6277181 ×2
  • Plate 1 x 1 White Part 3024 Element 6548262 or 302401 ×2
  • Plate 1 x 2 White Part 3023 Element 6552100 or 6548261 ×1
  • Plate 1 x 4 White Part 3710 Element 6552108 or 6548266 ×2
  • Plate 1 x 6 White Part 3666 Element 6552107 or 6548265 ×2
  • Plate 2 x 12 White Part 2445 Element 6552091 or 244501 ×3
  • Plate 2 x 16 White Part 4282 Element 6609534 or 4119227 ×3
  • Plate 2 x 2 White Part 3022 Element 6552099 or 6548260 ×4
  • Plate 2 x 4 White Part 3020 Element 6552098 or 302001 ×1
  • Plate 2 x 6 White Part 3795 Element 6550146 or 379501 ×2
  • Plate 4 x 10 White Part 3030 Element 6550137 or 4503008 ×1
  • Plate 4 x 6 White Part 3032 Element 303201 ×1
  • Plate Round 1 x 1 with Solid Stud White Part 6141 Element 6601919 or 614101 ×2
  • Plate Special 2 x 2 with Groove and Center Stud (Jumper) White Part 87580 Element 6550157 or 6126046 ×6
  • Technic Brick 1 x 12 [11 Pin Holes] White Part 3895 Element 6332157 or 6215045 ×2
  • Technic Brick 1 x 16 [15 Pin Holes] White Part 3703 Element 4508661 or 370301 ×2
  • Tile 1 x 1 with Groove White Part 3070b Element 6550138 or 307001 ×6
  • Tile 1 x 2 with Groove White Part 3069b Element 6548264 or 306901 ×2
  • Tile 1 x 8 with Groove White Part 4162 Element 6552110 or 416201 ×2
  • Tile 2 x 2 with Groove White Part 3068b Element 6548263 or 306801 ×14
  • Tile 2 x 4 with Groove White Part 87079 Element 6548271 or 4560178 ×16
  • Tile Special 1 x 1 with Clip with Rounded Edges White Part 15712 Element 6348055 or 6054551 ×1

Reddish Brown 135 pieces

  • Brick 1 x 2 x 2 with Inside Stud Holder Reddish Brown Part 3245c Element 6172808 or 4609329 ×14
  • Brick 1 x 2 x 5 with Hollow Studs Reddish Brown Part 2454b Element 4277016 ×18
  • Brick 1 x 4 Reddish Brown Part 3010 Element 4211225 ×8
  • Brick 2 x 2 Reddish Brown Part 3003 Element 4211210 ×11
  • Brick 2 x 2 Corner Reddish Brown Part 2357 Element 4211200 ×22
  • Brick 2 x 4 Reddish Brown Part 3001 Element 4211201 ×10
  • Brick 2 x 8 Reddish Brown Part 3007 Element 6096701 or 6037401 ×2
  • Plate 1 x 1 Reddish Brown Part 3024 Element 4221744 Also in Dark Brown ×1
  • Plate 1 x 4 Reddish Brown Part 3710 Element 4211190 ×2
  • Plate 1 x 8 Reddish Brown Part 3460 Element 4216945 ×2
  • Plate 2 x 2 Reddish Brown Part 3022 Element 4613975 or 4216695 ×4
  • Plate 2 x 2 Corner Reddish Brown Part 2420 Element 4211257 ×7
  • Plate 2 x 4 Reddish Brown Part 3020 Element 4211186 ×12
  • Plate 2 x 6 Reddish Brown Part 3795 Element 4211247 ×2
  • Plate 2 x 8 Reddish Brown Part 3034 Element 4211211 ×2
  • Plate 4 x 4 Reddish Brown Part 3031 Element 4243838 or 4225868 ×3
  • Plate Special 1 x 2 with Door Rail Reddish Brown Part 32028 Element 4645103 or 4541288 ×4
  • Plate Special 4 x 4 with 2 x 2 Opening Reddish Brown Part 64799 Element 6070442 ×4
  • Technic Beam 1 x 15 Thick Reddish Brown Part 32278 Element 6502375 or 6351287 ×2
  • Tile 1 x 2 with Groove Reddish Brown Part 3069b Element 4211151 ×1
  • Tile 2 x 2 with Groove Reddish Brown Part 3068b Element 4271949 or 4264030 ×4

Dark Orange 109 pieces

  • Brick 1 x 2 Dark Orange Part 3004 Element 4579659 or 4164441 ×9
  • Brick 1 x 4 Dark Orange Part 3010 Element 6223040 or 4597484 ×3
  • Brick 1 x 6 Dark Orange Part 3009 Element 6000743 or 4649911 ×2
  • Brick 2 x 2 Dark Orange Part 3003 Element 6212081 or 4597486 ×32
  • Brick 2 x 8 Dark Orange Part 3007 Element 6351290 ×12
  • Plate 1 x 4 Dark Orange Part 3710 Element 6074892 or 4603740 ×6
  • Plate 1 x 6 Dark Orange Part 3666 Element 6253418 or 4244385 ×2
  • Plate 2 x 10 Dark Orange Part 3832 Element 6351327 or 6131797 ×3
  • Plate 2 x 12 Dark Orange Part 2445 Element 6351289 ×3
  • Plate 2 x 2 Dark Orange Part 3022 Element 4615606 or 4603741 ×2
  • Plate 2 x 4 Dark Orange Part 3020 Element 4535928 or 4164449 ×3
  • Plate 2 x 6 Dark Orange Part 3795 Element 6219673 or 4603745 ×1
  • Plate Special 2 x 2 with Groove and Center Stud (Jumper) Dark Orange Part 87580 Element 6315197 ×6
  • Plate Special 2 x 4 with Groove and Two Center Studs (Jumper) Dark Orange Part 65509 Element 6288614 ×2
  • Tile 1 x 2 with Groove Dark Orange Part 3069b Element 4614158 or 4178112 ×2
  • Tile 1 x 8 with Groove Dark Orange Part 4162 Element 6351291 or 4244384 ×2
  • Tile 2 x 2 with Groove Dark Orange Part 3068b Element 6186423 ×9
  • Tile 2 x 4 with Groove Dark Orange Part 87079 Element 6058089 ×10

Black 84 pieces

  • Plate 1 x 1 Black Part 3024 Element 302426 ×2
  • Plate Round 2 x 2 with Axle Hole Type 1 (+ Opening) Black Part 4032a Element 403226 ×11
  • Technic Axle 12 Black Part 3708 Element 370826 ×1
  • Technic Axle 4 Black Part 3705 Element 370526 ×5
  • Technic Brick 1 x 14 [13 Pin Holes] Black Part 32018 Element 4107558 Also in Dark Bluish Gray ×2
  • Technic Brick 6 x 8 with 4 x 6 Opening Black Part 32532 Element 6448394 or 4188143 ×5
  • Technic Pin with Friction Ridges Lengthwise with No Center Slots Black Part 61332 Element 6279875 ×58

Medium Nougat 36 pieces

  • Bar 1 x 4 x 3 [End Tabs] Medium Nougat Part 62113 Element 6167599 ×4
  • Brick 1 x 2 with Reddish Brown and Dark Brown Lines Print Medium Nougat Part 3004pr0014 Element 6097024 ×2
  • Plate 2 x 12 Medium Nougat Part 2445 Element 6351301 ×1
  • Plate 2 x 2 Medium Nougat Part 3022 Element 6056383 or 4645059 ×2
  • Plate 2 x 4 Medium Nougat Part 3020 Element 6093494 or 4645061 ×4
  • Plate 2 x 6 Medium Nougat Part 3795 Element 6313600 ×4
  • Plate 6 x 6 Medium Nougat Part 3958 Element 6351288 or 6162899 ×14
  • Plate Special 2 x 2 with Groove and Center Stud (Jumper) Medium Nougat Part 87580 Element 6102994 ×2
  • Tile 2 x 2 with Dark Brown Minecraft Grid Print (Crafting Table) Medium Nougat Part 3068bpr0236 Element 6097003 ×1
  • Treasure Chest Bottom with Rear Slots, No Groove Medium Nougat Part 4738c Element 6102984 ×1
  • Treasure Chest Lid [Thick Hinge] Medium Nougat Part 4739a Element 6254218 or 6167286 ×1

Light Bluish Gray 31 pieces

  • Animal Body Part, Cat Head 1 x 2 with Cube with Ears, Nose and Pixelated Face with Tan Eyes and Dark Bluish Grey Nose Print (Cat) Light Bluish Gray Part 24008pr0006 Element 6347335 ×1
  • Bracket 3 x 2 x 1 1/3 with Pin Bottom Light Bluish Gray Part 18671 Element 6093054 ×2
  • Plate 1 x 1 Light Bluish Gray Part 3024 Element 4211399 ×2
  • Plate 1 x 3 Light Bluish Gray Part 3623 Element 4211429 or 3623194 ×1
  • Plate Special 1 x 2 with Clip Horizontal on End Light Bluish Gray Part 63868 Element 6319336 or 4535738 ×9
  • Plate Special 1 x 2 with Handle on End [Closed Ends] Light Bluish Gray Part 60478 Element 4515369 ×1
  • Technic Beam 1 x 15 Thick Light Bluish Gray Part 32278 Element 4542577 or 4211770 ×2
  • Technic Brick 1 x 4 [3 Pin Holes] Light Bluish Gray Part 3701 Element 4211441 ×8
  • Technic Brick 4 x 4 with 2 x 2 Opening Light Bluish Gray Part 32324 Element 4211640 ×3
  • Tile 1 x 1 with Groove Light Bluish Gray Part 3070b Element 4211415 ×1
  • Tile 1 x 2 with Groove Light Bluish Gray Part 3069b Element 4211414 ×1

Dark Bluish Gray 26 pieces

  • Brick 1 x 2 with Pixelated Forge Print Dark Bluish Gray Part 3004pr0021 Element 6216860 ×1
  • Brick 1 x 2 with Pixelated Lit Forge Print Dark Bluish Gray Part 3004pr0020 Element 6216862 ×1
  • Brick Special 1 x 2 with Vertical Clip [Open O Clip] Dark Bluish Gray Part 30237b Element 6335306 or 6127738 ×4
  • Brick Special 2 x 2 with Pin and Axle Hole Dark Bluish Gray Part 6232 Element 6408023 or 4211046 ×6
  • Plate 1 x 2 Dark Bluish Gray Part 3023 Element 4211063 ×1
  • Plate 2 x 2 Dark Bluish Gray Part 3022 Element 4211094 ×2
  • Plate 2 x 2 Corner Dark Bluish Gray Part 2420 Element 4210635 ×1
  • Plate 2 x 4 Dark Bluish Gray Part 3020 Element 4211065 ×2
  • Plate 4 x 4 Dark Bluish Gray Part 3031 Element 4243831 or 4211089 ×1
  • Plate Special 2 x 2 with Groove and Center Stud (Jumper) Dark Bluish Gray Part 87580 Element 6126083 or 4565322 ×1
  • Technic Brick 1 x 12 [11 Pin Holes] Dark Bluish Gray Part 3895 Element 4210963 ×2
  • Technic Brick 1 x 14 [13 Pin Holes] Dark Bluish Gray Part 32018 Element 4211137 Also in Black ×2
  • Tile 1 x 2 with Groove Dark Bluish Gray Part 3069b Element 4211052 ×1
  • Tile 1 x 3 Dark Bluish Gray Part 63864 Element 4568734 ×1

Dark Brown 22 pieces

  • Equipment Telescope / Torch / Spyglass, Support Round 1 x 1 x 1 2/3 Dark Brown Part 64644 Element 4538950 ×4
  • Plate 1 x 1 Dark Brown Part 3024 Element 6194729 or 6013830 Also in Reddish Brown ×8
  • Technic Brick 1 x 2 with Axle Hole Type 1 [+ Opening] and Bottom Pin Dark Brown Part 32064a Element 6272144 ×10

Lime 21 pieces

  • Brick 1 x 1 Lime Part 3005 Element 4220634 or 4122446 ×4
  • Brick 1 x 3 Lime Part 3622 Element 4166093 or 4122448 ×4
  • Brick Special 1 x 1 Studs on 4 Sides Lime Part 4733 Element 6174006 or 4212458 ×1
  • Plate 1 x 1 Lime Part 3024 Element 4621557 or 4561480 ×4
  • Plate 1 x 2 Lime Part 3023 Element 4164037 or 4122439 ×4
  • Tile 1 x 2 with Groove Lime Part 3069b Element 4500125 or 4164025 ×4

Dark Tan 17 pieces

  • Plate 1 x 1 Dark Tan Part 3024 Element 4549436 or 4497084 ×1
  • Plate 4 x 4 Corner Dark Tan Part 2639 Element 6151537 ×4
  • Tile 2 x 2 with Groove Dark Tan Part 3068b Element 4507045 or 4251986 ×12

Yellow 15 pieces

  • Brick 2 x 2 Yellow Part 3003 Element 4103588 or 300374 ×10
  • Plate Round 1 x 1 with Solid Stud Yellow Part 6141 Element 614124 ×2
  • Technic Axle 3 Yellow Part 4519 Element 6130007 ×1
  • Technic Beam 1 x 11 Thick Yellow Part 32525 Element 6028107 or 4534912 ×2

Bright Green 11 pieces

  • Plate 1 x 2 Bright Green Part 3023 Element 6343326 or 6014491 ×1
  • Plate 4 x 4 Bright Green Part 3031 Element 4617799 or 4243836 ×1
  • Plate 6 x 6 Bright Green Part 3958 Element 6004650 or 4184006 ×5
  • Plate Round 1 x 1 with Solid Stud Bright Green Part 6141 Element 6109808 ×1
  • Tile 2 x 2 with Groove Bright Green Part 3068b Element 6294513 or 6138520 ×3

Red 11 pieces

  • Plate 1 x 1 Red Part 3024 Element 302421 ×4
  • Plate 2 x 2 Red Part 3022 Element 4613974 or 302221 ×1
  • Plate Special 2 x 2 with Groove and Center Stud (Jumper) Red Part 87580 Element 6126048 or 4581308 ×1
  • Technic Brick 1 x 12 [11 Pin Holes] Red Part 3895 Element 389521 ×2
  • Technic Brick 1 x 6 [5 Pin Holes] Red Part 3894 Element 389421 ×1
  • Technic Pin Long with Friction Ridges Lengthwise and Stop Bush [2 Lateral Holes, Small Pin Hole] Red Part 65304 Element 6347789 ×2

Dark Green 9 pieces

  • Tile 1 x 1 with Groove Dark Green Part 3070b Element 6618080 or 6055171 ×9

Blue 8 pieces

  • Brick 1 x 1 Blue Part 3005 Element 300523 ×2
  • Plate 2 x 4 Blue Part 3020 Element 4240375 or 302023 ×1
  • Plate 6 x 8 Blue Part 3036 Element 303673 or 303623 ×2
  • Technic Pin Long with Friction Ridges Lengthwise, 1 Center Slot Blue Part 42924 Element 6299413 ×2
  • Tile 2 x 4 with Groove Blue Part 87079 Element 4654678 or 4560180 ×1

Trans-Dark Blue 8 pieces

  • Brick 2 x 2 without Inside Ridges Trans-Dark Blue Part 6223 Element 6514091 or 6238043 ×3
  • Brick Sloped 45° 2 x 2 Trans-Dark Blue Part 3039 Element 6514101 or 6244887 ×1
  • Plate 1 x 2 Trans-Dark Blue Part 3023 Element 6514004 or 6240215 ×4

Bright Light Orange 4 pieces

  • Plant, Carrot Top Bright Light Orange Part 33183 Element 6096682 ×2
  • Plate 2 x 4 Bright Light Orange Part 3020 Element 6097511 ×2

Bright Pink 4 pieces

  • Plate 1 x 1 Bright Pink Part 3024 Element 6031883 or 4599540 ×2
  • Plate 2 x 4 Bright Pink Part 3020 Element 6204535 or 4245288 ×2

Trans-Brown 4 pieces

  • Panel 1 x 6 x 5 Trans-Brown Part 59349 Element 6245429 ×4

Trans-Orange 4 pieces

  • Plate 1 x 1 Trans-Orange Part 3024 Element 6513961 or 6252040 ×4

Trans-Yellow 4 pieces

  • Plate 1 x 1 Trans-Yellow Part 3024 Element 6513966 or 6252045 ×4

Magenta 3 pieces

  • Tile 1 x 2 with Groove Magenta Part 3069b Element 4611415 ×2
  • Tile 2 x 2 with Groove Magenta Part 3068b Element 6249234 or 4173214 ×1

Tan 2 pieces

  • Plate 2 x 4 Tan Part 3020 Element 4114309 or 302005 ×2

Bright Light Blue 1 piece

  • Animal, Fish [Hollow Stud Mouth] Bright Light Blue Part 64648 Element 6195347 ×1

Flat Silver 1 piece

  • Tool Pickaxe Blocky, Double Flat Silver Part 18789 Element 6104264 ×1

Medium Azure 1 piece

  • Plate Round 1 x 1 with Solid Stud Medium Azure Part 6141 Element 6102986 ×1

Orange 1 piece

  • Brick and Axle Separator v2.0 Orange Part 96874 Element 6240515 or 4654448 ×1

Pearl Gold 1 piece

  • Weapon Sword Blocky Pearl Gold Part 18787 Element 6093621 ×1

Trans-Clear 1 piece

  • Tile Round 1 x 1 with Brown and Tan Squares Print Trans-Clear Part 98138pr0078 Element 6274784 or 6215145 ×1

Trans-Green 1 piece

  • Brick 2 x 2 without Inside Ridges Trans-Green Part 6223 Element 6514090 or 6219774 ×1

Minifigures 4 figures

  • Zombie Minifigure, checked as a whole figure ×1
  • Charged Creeper Minifigure, checked as a whole figure ×1
  • Panda Skin Minifigure, checked as a whole figure ×1
  • Ocelot Skin Minifigure, checked as a whole figure ×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.

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