Door key
A door key is a small metal tool designed to operate the lock mechanism of a door.
How big is it?
5.5 cm long
Also 2.165 in
Length · example
A little perspective
Door key vs Cleaner shrimp: length comparison
The length of a door key is approximately equal to the body length of a cleaner shrimp.
A door key is a small metal tool designed to operate the lock mechanism of a door.
A cleaner shrimp is a marine crustacean that removes parasites and dead tissue from fish, forming mutualistic relationships.
Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions. Horizontal rulers compare the selected spans; vertical brackets also identify height on the artwork.
Measurements, assumptions & sources +
Door key
Length: 5.5 cm; example.
A chosen 55 mm, 9 g household key.
Defined examples — our methodology
The marked length is calibrated. Unmeasured illustration details are representative.
Cleaner shrimp
Defined body length: 5.5 cm; defined specimen; range 4 cm–7 cm.
A defined 5.5 cm skunk cleaner shrimp measured from rostrum to tail fan. Long white antennae extend beyond and are excluded from body length.
Smithsonian Ocean — Cleaner shrimp
The marked defined body length is calibrated. Unmeasured illustration details are representative.
Use the visual comparison to explore its scale, then check the measurements and sources.
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Why this measurement?
Why we use 5.5 cm
We compare the length of a door key. This is an illustrative comparison value, not a claim that every example is the same.
A chosen 55 mm, 9 g household key.
The marked vertical span follows the measured feature, not the edges of the image. How calibrated comparisons work →
Recorded properties
Dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 5.5 cm | Not recorded | example | |
| 9 g | Not recorded | example |
Around this scale
Explore nearby values.
Compare examples with lower, similar and higher values. Each card names the measurement being compared.
Nearest lower valueEveryday objectsPlum5 cmDefined fruit diameterA plum is a sweet, edible fruit produced by trees of the genus Prunus, containing a single hard stone.
Around the same scaleLiving thingsCleaner shrimp5.5 cmDefined body lengthA cleaner shrimp is a marine crustacean that removes parasites and dead tissue from fish, forming mutualistic relationships.
Nearest higher valueSport and equipmentPelota ball5.7 cmDefined ball diameterA pelota ball is a hard ball used in Basque pelota, a traditional court sport played by striking the ball against a wall.Sources and method
Want to check the number?
The source records and measurement method remain available for inspection.
More ways to see it
Curated comparisons
There’s always another scale
Follow your curiosity.
PeopleHuman1.75 mA human is a primate of the species Homo sapiens, distinguished by habitual upright walking, language and complex tool use.
TransportFamily car4.5 mA family car is a motor vehicle designed to carry several passengers and their belongings.
TransportDouble-decker bus11 mA double-decker bus is a passenger vehicle with two levels, used for public transport.Living thingsCleaner shrimp5.5 cmA cleaner shrimp is a marine crustacean that removes parasites and dead tissue from fish, forming mutualistic relationships.Everyday thingsPlum5 cmA plum is a sweet, edible fruit produced by trees of the genus Prunus, containing a single hard stone.
SportLacrosse ball6.35 cmA lacrosse ball is a solid rubber ball used in the sport of lacrosse, designed to meet official standards for play.
ContainersEspresso demitasse60 mlAn espresso demitasse is a small porcelain cup used for serving concentrated espresso coffee.
Living thingsAntarctic krill6 cmAntarctic krill (Euphausia superba) are small, shrimp-like marine crustaceans that serve as a vital food source for many Antarctic animals.