Half of the Part + Color Combinations in Our Catalog Appear in Only One Set
We count how often each part and color combination appears in our catalog. The results describe catalog rarity, not the cost or feasibility of replacing a piece.
The June 2026 analysis covered 1,131,058 inventory records across 26,086 catalog entries dated 1949–2026. Of 91,650 distinct part and color combinations, 46,619 (51%) were recorded in exactly one set. Another 20% were recorded in two or three. These are observations about this database snapshot, not a complete count of every LEGO part ever produced.
What the score measures
For each part and color combination, we count distinct set numbers with a non-spare inventory entry. The per-set score is the percentage of its distinct combinations recorded in three or fewer sets. Each combination counts once, regardless of how many copies the set uses.
A score of 0% means every recorded combination occurs in at least four sets in the catalog, including the set being viewed. It does not mean zero repair risk. A high score means more combinations occur in few catalog entries; it does not mean replacements are unavailable.
The historical API and CSV field names include repair_risk and hard_to_replace. Those names remain for compatibility. The underlying metric measures catalog frequency only; we corrected the stronger replacement claims on 1 October 2026.
What it cannot tell you
The calculation does not measure production quantities, seller stock, prices, shipping costs, regional availability or compatible substitute molds. A piece found in one mass-produced set may be easy to buy separately. A piece found in many older sets may still be difficult to source.
Catalog coverage and inventory completeness affect the result. Different catalogs split molds, printed parts and element IDs differently. Our counts include entries such as bulk tubs, education sets, service packs and promotional sets. Counts and rankings cannot be assumed to agree across catalogs.
Newer parts have had less time to appear in additional sets. Minifigure components are largely absent from these inventories because minifigures are modeled separately. These limitations matter when comparing themes or release periods.
Method and snapshot dates
The initial study reported scores for 12,753 sets with at least 30 parts and a known release year. The downloadable July export applies a minimum of 30 parts and 15 distinct part and color combinations, giving about 11,900 rows. The two snapshots and selection rules are different; their totals should not be treated as interchangeable.
The live catalog can change as inventories are added or corrected. Set-page scores may therefore differ from the archived study. The published files below retain their existing column names and values; this clarification does not recalculate the dataset.
Download the dataset
The July 2026 export is available under CC BY 4.0. Credit BrickMissing and link to this methodology when reusing the data.
- Part and color frequency (CSV)
Distinct set counts for combinations recorded in the export; spares excluded.
- Per-set catalog rarity (CSV)
Share of recorded combinations appearing in three or fewer sets, using legacy field names.
- Dataset documentation
Column definitions, scope and limitations.
- Archived dataset on Zenodo
The archive may retain the original wording; use the limitations explained here when interpreting its values.
Use the catalog to identify the exact part and color you need. Check current supplier listings separately before deciding whether a replacement is available or affordable.