How to Check if a LEGO Set Is Complete

Whether you bought a LEGO set at a yard sale, found one in a relative's attic, or just took a long-finished build apart and want to be sure you have everything before rebuilding — the question is the same: is this set complete? This guide is the practical workflow.

Step 1: Identify the set first

You can't check completeness without knowing the set number. If you're not sure which set you have, run that down before anything else:

• Set number on the box, instruction booklet, or printed brick — fastest path.
• If no number, identify the set from a photo using the LegoFinder identifier or by following our guide on identifying LEGO from loose bricks.

Once you have the set number, the rest of this guide assumes you know which inventory to check against.

Step 2: Get the parts inventory from Rebrickable

Go to rebrickable.com, search the set number, and open the set page. Each set has an "Inventory" tab listing every part the set should contain — part number, color, quantity, and a thumbnail. This is your checklist.

Print the inventory or keep it open on a phone or tablet next to where you're sorting. For larger sets, a printed copy is much faster to work with than scrolling on a phone.

Step 3: Sort the bricks before counting

Resist the temptation to check the inventory in order. Sorting first, counting second, is dramatically faster. Recommended approach:

Quick sort (good for small sets, 100–400 pieces)

1. Sort by color first — all red, all blue, all light bluish gray, etc.
2. Within each color, sort by part type — bricks together, plates together, slopes together, specialty pieces in their own pile.
3. Now scan the Rebrickable inventory by colour. For each colour group, check off each line as you find the parts.

Detailed sort (sets over 400 pieces)

1. Sort by part type first — all bricks regardless of colour, all plates regardless of colour, etc.
2. Within each type, group by size (2×2, 2×3, 2×4, 1×2, etc.).
3. This makes counting specific brick variants much faster than scanning the whole pile for one colour at a time.

Step 4: Check the high-value items first

Not all missing parts are equal. Two missing 1×1 round plates barely affect the build. A missing printed cockpit tile or a missing minifigure renders the set incomplete in a way that matters. Check these in priority order:

1. Minifigures. Are all the figures present? Each minifigure consists of a head, a torso, legs, and (usually) a hat or hair piece. Many sets also include accessories — weapons, capes, tools.
2. Printed bricks and tiles. Look for any piece with a printed image, decal, or sticker. These are set-specific and irreplaceable from generic LEGO supply.
3. Stickers. If the original set included stickers, check whether the sticker sheet is present (or whether the previous owner already applied them).
4. Specialty parts. Vehicle chassis, large baseplates, custom moulds. These are hard to source replacements for.
5. Common bricks. Generic 2×4 bricks, basic plates. These are easy to replace and affect completeness least.

Step 5: What "complete" actually means

Two important calibrations:

Spare pieces

LEGO ships extra small pieces (1×1 plates, small clips, technic pins) in most sets. If you have one or two more of a small part than the inventory says, that's normal — those are spares, not extras.

Variant pieces

Some retired sets exist in two production runs with subtly different parts (e.g. a slightly different printed minifigure variant or a different mould of the same brick). Rebrickable usually lists both variants. If your part isn't an exact match but is the right type, it may be a known variant.

Step 6: Filling in missing parts

If your set is missing parts, three options:

BrickLink

The standard marketplace. Open BrickLink, find the set's parts list, and identify exactly which part numbers and colours you're missing. Order from a single seller when possible to save on shipping. Most common parts cost $0.05–0.50 each plus shipping; printed and rare parts cost more.

LEGO Bricks & Pieces (official)

LEGO's own service at lego.com/service/replacementparts. Less complete catalogue than BrickLink, but for current and recently-retired parts, often cheaper and ships directly from LEGO.

Cannibalize from duplicate sets

If you have multiple copies of common bricks from other sets, you can complete a missing set with parts from your existing inventory. Most builders are comfortable with this for non-printed pieces.

Step 7: Rebuild as a final completeness check

The ultimate test: try to build the set following the instructions. If you make it to the end without running out of pieces or substituting, the set is complete. Some builders skip the inventory check and go straight to building — risky for large sets, but for under-300-piece sets it's often faster than detailed checking.

For sealed sets (still in box)

Don't open them to check completeness. Sealed-box value drops significantly once opened, and modern factory-sealed sets are nearly always complete. The exceptions:

• Sets sold on the second-hand market labelled "sealed" — verify the original factory tape is intact, not resealed with clear plastic tape later.
• Very old sets where original box quality matters more than contents.

If you have a sealed set you suspect was tampered with: check the LEGO Group's official factory tape pattern (a continuous LEGO logo strip with no joins) versus what's on your box. Mismatched tape is the most common reseal indicator.

See also

• How to identify a LEGO set from loose bricks — when you don't know the set number yet.
• LEGO storage and organization — for keeping your collection sortable.
• How to find LEGO building instructions — once the set is complete.