Archived reference library
Find a length you can picture.
29 references: 21 sourced objects and 8 exact units. Explore definitions, sources and comparisons.
406 unordered conversion pairs, excluding self-pairs. Choose any two references to compare their defined lengths.
This preserves the 2026-10-18 catalogue. Browse current references.
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Browse 16 categories
Metric
4 referenceslength
Exact unit definition
1 mm
length
Exact unit definition
1 cm
length
Exact unit definition
1 m
length
Exact unit definition
1 km
US customary / imperial
4 referenceslength
Exact unit definition
1 in
length
Exact unit definition
1 ft
length
Exact unit definition
1 yd
length
Exact unit definition
1 mi
Everyday objects
2 referenceslong edge
Nominal standard size
≈ 85.60 mm
long edge
Nominal standard size
≈ 297 mm
Coins
1 referencediameter
Manufacturer specification
≈ 24.26 mm
Fruits
1 referencediameter
Documented sample mean
≈ 7.63 cm
Vegetables
1 referenceroot length, without foliage
Chosen midpoint of a documented range
≈ 6.5 in
Toys
1 referenceassembled model length
Rounded manufacturer reference
≈ 84 cm
Sports
3 referencesdiameter
Nominal standard size
≈ 40 mm
playing-surface length
Nominal standard size
≈ 2.74 m
pitch length
Nominal standard size
≈ 22 yd
Aircraft
2 referencesfull tip-to-tip wingspan
Rounded manufacturer reference
≈ 68.4 m
overall length
Rounded manufacturer reference
≈ 72.7 m
Electronics
2 referencesoverall width, with controllers
Manufacturer specification
≈ 242 mm
case width
Manufacturer specification
≈ 60.6 mm
Science
1 referenceprimary-mirror diameter
Published reference measurement
≈ 6.5 m
Spacecraft
2 referencesvehicle length, without extended arm
Published reference measurement
≈ 3 m
rotor tip-to-tip span
Published reference measurement
≈ 1.2 m
Landmarks
1 referenceclock-dial diameter
Published reference measurement
≈ 7 m
Animals
1 referencewingspan
Chosen midpoint of a documented range
≈ 3.5 in
Fiction
1 referenceofficial Pokédex height
Official fictional reference
≈ 0.4 m
