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.

Checking

77256 Time Machine from Back to the Future

348 pieces in 147 part and color combinations, plus 2 minifigures.

The official piece count includes the 9 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. 3 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 28 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.

Brick Sloped 30° 1 x 1 x 2/3 (Cheese Slope) Black ×3 Dark Bluish Gray ×2 Black is darker than Dark Bluish Gray.
Plate Special 1 x 2 Rounded with 2 Open Studs Black ×4 Dark Bluish Gray ×6 Black is darker than Dark Bluish Gray.
Plate Special 2 x 2 with Only 2 studs Black ×3 Dark Bluish Gray ×1 Black is darker than Dark Bluish Gray.

Piece checklist

Plates Round Curved and Dishes 34 pieces

Dish 2 x 2 Inverted [Radar] with Turbine, Orange/Silver Stripes Print Black Part 4740pr0022 Element 6585377 ×1
Plate Round 1 x 1 with Open Stud Black Part 85861 Element 6168646 or 6100627 1 spare in the box ×3
Plate Special 1 x 2 Rounded with 2 Open Studs Black Part 35480 Element 6210270 Also in Dark Bluish Gray ×4
Plate Special 1 x 3 Rounded with 3 Open Studs Black Part 77850 Element 6428168 ×5
Plate Round 1 x 1 with Solid Stud Blue Part 6141 Element 614123 1 spare in the box ×13
Plate Special 1 x 2 Rounded with 2 Open Studs Dark Bluish Gray Part 35480 Element 6221607 Also in Black ×6
Plate Special 1 x 3 Rounded with 3 Open Studs White Part 77850 Element 6550184 or 6450820 ×2

Tiles Round and Curved 14 pieces

Tile Round 1 x 1 Half Circle Black Part 24246 Element 6256435 1 spare in the box ×1
Tile Round 1 x 1 Quarter Black Part 25269 Element 6172383 1 spare in the box ×2
Tile Round 2 x 2 with Black Hubcap Print Flat Silver Part 14769pr0026 Element 6585385 ×4
Tile Round 1 x 1 Red Part 98138 Element 6284574 or 6063445 1 spare in the box ×2
Tile 2 x 2 Curved, Macaroni with Silver Plating Print Trans-Light Blue Part 7836pr0001 Element 6585391 ×4
Tile Round 1 x 1 White Part 98138 Element 6564903 or 6284572 1 spare in the box ×1

Bricks Curved 11 pieces

Brick Curved 2 x 2 x 2/3 Black Part 15068 Element 6053077 ×2
Brick Curved Inverted 2 x 2 x 2/3 Black Part 32803 Element 6211476 ×3
Brick Curved 2 x 1 No Studs with Silver Plating Print Trans-Light Blue Part 11477pr0036 Element 6585390 ×6

Technic Pins 10 pieces

Technic Pin 1/2 with Friction Dark Bluish Gray Part 89678 Element 6395635 1 spare in the box ×2
Technic Pin 1/2 without Friction Ridges Light Bluish Gray Part 4274 Element 4274194 or 4211483 1 spare in the box ×4
Technic Axle Pin without Friction Ridges Lengthwise Tan Part 3749 Element 4666579 or 4186017 ×4

Hinges, Arms and Turntables 8 pieces

Hinge Plate 1 x 2 Locking with 2 Fingers On End, without Groove, 7 Teeth Black Part 54657 Element 6267045 ×4
Hinge Brick 1 x 2 Base Light Bluish Gray Part 3937 Element 4211469 ×2
Hinge Brick 1 x 2 Top Plate Thin Light Bluish Gray Part 3938 Element 4211470 ×2

Transportation - Land 8 pieces

Spoiler, Plate Special 1 x 2 Black Part 30925 Element 6218700 ×2
Steering Wheel Small, 2 x 2 [Reinforced] Black Part 16091 Element 6057397 ×1
Vehicle Base 6 x 12 x 1 with Holes, 6 Studs On sides, 1 x 2 Cutouts on Ends Black Part 3385 Element 6605193 or 6424673 ×1
Wheel Arch, Mudguard 4 x 2 1/2 x 1 Light Bluish Gray Part 98282 Element 6593246 or 6407751 ×4

Minifig Accessories 7 pieces

Equipment Fishing Rod 12L, Vertical Line Hole Black Part 2614 Element 6270122 ×1
Musical Instrument Microphone [Plain] Black Part 90370 Element 6088550 1 spare in the box ×1
Equipment Binoculars Dark Bluish Gray Part 30162 Element 4587887 or 4211051 ×1
Equipment Telescope / Torch / Spyglass, Support Round 1 x 1 x 1 2/3 Light Bluish Gray Part 64644 Element 4657366 ×2
Sports Roller Skate Light Bluish Gray Part 11253 Element 6217791 1 spare in the box ×2

Bars, Ladders and Fences 6 pieces

Bar, Curved U-Shape 2 x 3 Dark Blue Part 7052 Element 6535351 ×1
Bar 2L with Stop in Center Dark Bluish Gray Part 78258 Element 6350724 1 spare in the box ×1
Bar 5L with Handle (Friction Ram) Light Bluish Gray Part 87618 Element 4565433 ×2
Bar 2L with Stop in Center Red Part 78258 Element 6399645 1 spare in the box ×1
Bar Holder with Clip Sand Green Part 11090 Element 6341975 or 6226411 ×1

Bricks 6 pieces

Brick 1 x 2 Black Part 3004 Element 300426 ×1
Brick 1 x 2 with 'NOV 05 1955', 'OCT 26 1985', 'OCT 26 1985' Print Black Part 3004pr0009 Element 6585376 ×1
Brick 1 x 1 Dark Bluish Gray Part 3005 Element 4211098 ×2
Brick 1 x 6 Dark Bluish Gray Part 3009 Element 4211100 ×1
Brick 2 x 4 Red Part 3001 Element 300121 ×1

Windows and Doors 6 pieces

Window 1 x 2 x 2 Flat Front Dark Bluish Gray Part 60592 Element 6396397 or 4523049 ×2
Window 1 x 2 x 2 Plane, Hollow Studs, Single Hole Top and Bottom for Glass Light Bluish Gray Part 60032 Element 6565395 ×1
Glass for Window 1 x 2 x 2 Flat with Dark Bluish Grey Headlights Print Trans-Clear Part 60601pr0017 Element 6585380 ×2
Glass for Window 1 x 2 x 2 Flat with Flux Capacitor Print Trans-Clear Part 60601pr0016 Element 6585378 ×1

Wheels and Tyres 4 pieces

Wheel Rim 24 x 13.4 with Black Slick Tyre [Soft Rubber] Flat Silver Part 7056 Element 6597150 ×4

Bricks Round and Cones 3 pieces

Brick Round 2 x 2 Truncated Cone Black Part 98100 Element 4653822 ×1
Brick Round 1 x 1 with Black 'MR. FUSION' Print White Part 3062bpr0016 Element 6585387 ×1
Cone 1 1/2 x 1 1/2 x 2/3 White Part 33492 Element 6523388 ×1

Panels 3 pieces

Panel 1 x 2 x 1 [Rounded Corners] Black Part 4865b Element 6146220 ×2
Panel 1 x 4 x 2 with Side Supports - Hollow Studs Light Bluish Gray Part 14718 Element 6061675 ×1

Pneumatics 3 pieces

Pneumatic Hose Connector with Axle Connector Dark Bluish Gray Part 99021 Element 6265669 or 6020189 ×3

Bricks Wedged 2 pieces

Brick Wedged, Curved 2 x 1 with Stud Notch Left Light Bluish Gray Part 29120 Element 6225139 ×1
Brick Wedged, Curved 2 x 1 with Stud Notch Right Light Bluish Gray Part 29119 Element 6225142 ×1

Minifig Upper Body 2 pieces

Arm Skeleton [Bent / 2 Clips] Black Part 93609 Element 6326681 or 6146095 ×2

Plates Wedged 2 pieces

Wedge Plate 2 x 2 Left Light Bluish Gray Part 24299 Element 6163478 ×1
Wedge Plate 2 x 2 Right Light Bluish Gray Part 24307 Element 6163477 ×1

Technic Axles 2 pieces

Technic Axle 3 with Stud Dark Tan Part 6587 Element 6031821 or 6013821 ×2

Technic Connectors 2 pieces

Technic Axle and Pin Connector Perpendicular Black Part 6536 Element 6261371 or 4173668 ×2

Tubes and Hoses 2 pieces

Zipline, 22L with 2 Connectors - Flexible Black Part 27965 Element 6381295 ×2

Animal / Creature Body Parts 1 piece

Creature Body Part, Horn (Unicorn) Sand Green Part 89522 Element 6223215 or 6070905 1 spare in the box ×1

Minifig Shields, Weapons, & Tools 1 piece

Tool Screwdriver and Spanner / Wrench Flat Silver Part 4006 Element 6167576 ×1

Stickers 1 piece

Sticker Sheet for Set 77256-1 [No Color/Any Color] Part 10115856 Element 6585755 ×1

Windscreens and Fuselage 1 piece

Windscreen 6 x 6 x 1 1/3 with Black/Dark Bluish Grey Frame Print Trans-Clear Part 65633pr0022 Element 6585375 ×1

Minifigures 2 figures

Marty McFly, Puffer Vest Minifigure, checked as a whole figure ×1
Doc Brown 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.