Scaleidoscope — measurement converter and explorer of historical, scientific and unusual units

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Measurement of the day

Biblical ephah (common scholarly reconstruction)

The biblical ephah was the dry-measure counterpart of the liquid bath.

One Biblical ephah (common scholarly reconstruction) is understood to be about 0.022 cubic metres.

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Dimension
volume
Region
Mesopotamia / Levant
Era
Antiquity
Certainty
Historically reconstructed
approx.

Disagreement

Where humans could not agree

A cubit is not a cubit. These records refuse to collapse into one number, so the converter asks you to choose a tradition first.

Antiquity

Measured before there were standards

Rebuilt from surviving rods, temple walls and market weights — with the uncertainty left in.

Precision

The measurements we stopped arguing about

Fixed by international agreement and constants of nature. Exactly exact.

Scientific measurement records
metremLengthexact
kilometrekmLengthexact
centimetrecmLengthexact
millimetremmLengthexact
gramgMassexact
kilogramkgMassexact

Creativity

Strange & wonderful

Units invented by students, engineers, reindeer herders and jokers — recorded here with the same honesty as the metre.

Sheppey

Sheppey comes from Douglas Adams and John Lloyd's The Meaning of Liff: it is the closest distance at which sheep remain picturesque—approximately seven-eighths of a mile.

Invented for a joke. Documented anyway.

approx.informal

attoparsec

The Jargon File notes a delightful coincidence: an attoparsec is about an inch, and one attoparsec per microfortnight is about one inch per second.

Yes, that is really the name.

informal

beard-second

Its name looks singular, but the historically responsible calculator result is plural: users must choose among documented variants rather than receive one universal conversion.

Yes, that is really the name.

variantinformal

Beard-second (10 nm convention)

The 10 nm beard-second is the Physics Handbook convention cited in University of Leipzig mechanics material.

Yes, that is really the name.

informal

potrzebie

Knuth later recalled that MAD paid him $25 for the piece.

Invented for a joke. Documented anyway.

reference-only

pyramid inch

This record is included as a lesson in measurement history: a claim can be historically interesting without being scientifically valid.

Invented for a joke. Documented anyway.

discredited

Every measurement humans have agreed on — and the ones they never did.

196 approved records and 21 documented ambiguities. Where the evidence is a range, a reconstruction or a disagreement, Scaleidoscope says so instead of rounding history into a single number.

The whole library

196

measurements, sorted by what they physically measure — length, mass, time, and everything humans argued about in between.

Browse them all →

Occasional dispatches

The rabbit hole travels.

Wherever you are, the weirdest measurements can come to you.

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