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Span (span) - Unit Information & Conversion

Symbol:span
Plural:spans
Category:Length

What is a Span?

Definition

The Span is an ancient unit of length based on the distance across an outstretched human hand, measured from the tip of the thumb to the tip of the little finger (or sometimes the index finger). As an anthropomorphic unit, its length was inherently variable, depending on the size of an individual's hand.

Historically, it was often defined in relation to other body-based units:

  • Typically considered half a cubit.
  • Often equated to 3 palms (where a palm is the width of the hand across the base of the fingers).
  • Sometimes defined as 12 digits (fingerbreadths).

A common, though unofficial, modern estimate for a span is around 9 inches or approximately 22.86 centimeters (cm).

History

The span is one of the oldest informal units of measurement, used by numerous ancient civilizations, including the Egyptians, Israelites, Greeks, and Romans, due to the convenience of using the human hand.

  • Ancient Egypt & Mesopotamia: The span was used alongside the cubit and digit. The relationship (often 1 span = 1/2 cubit) was fundamental in their systems.
  • Biblical References: The span is mentioned in the Bible (e.g., Exodus 28:16 describing the High Priest's breastplate, Goliath's height in some interpretations).
  • Ancient Greece & Rome: Used as a practical subdivision of the cubit.
  • Medieval Europe: Continued in informal use and sometimes appeared in texts defining lengths. In England, it was often standardized (unofficially) as 9 inches.

Like other anthropomorphic units, the span fell out of official use with the development and adoption of more standardized systems like the Imperial (inches, feet) and Metric (meters) systems, which provided necessary precision for trade, science, and industry.

Common Uses

The span is now obsolete for precise or official measurements but is still encountered or used in specific contexts:

  • Informal Estimation: Used for quick, rough measurements of moderate lengths where precision is not critical (e.g., gardening, crafts, estimating object sizes).
  • Historical Texts: Found in ancient and medieval documents, requiring understanding for interpretation.
  • Anthropology & Archaeology: Relevant when studying historical measurement systems or interpreting dimensions from ancient sites.
  • Figurative Language: Can be used metaphorically to denote a small distance or extent ("life span").
  • Understanding Historical Units: Key to grasping the relationship between units like the digit, palm, and cubit in ancient systems.

Unit FAQs

How long is a span?

There is no single, universally fixed length for a span because it's based on human hand size. However:

  • A common historical and modern estimate is 9 inches (in).
  • This is approximately 22.86 centimeters (cm) or 0.2286 meters (m).
  • Historically, it was often defined as half a cubit, which varied (e.g., a common cubit of ~18 inches would yield a 9-inch span).

What is the relationship between a span and a cubit?

In many historical systems, a span was considered half (1/2) of a cubit. Since cubits themselves varied (e.g., common cubit vs. royal cubit), the exact length of the span derived this way also varied.

What is the relationship between a span and a palm or digit?

Common relationships, though varying by system, were:

  • 1 span ≈ 3 palms (where a palm is the width of the hand).
  • 1 span ≈ 12 digits (where a digit is the width of a finger).

Is the span an SI unit?

No, the span is not an SI unit. It is an ancient, non-standardized, anthropomorphic unit. The SI base unit for length is the meter (m).

Is the span still used today?

The span is not used for any official, scientific, or commercial measurements. Its use is limited to informal estimations, historical context, and figurative language. People might still use their own hand span for a quick size check.

Where does the name 'span' come from?

The word "span" comes from Old English spann, related to the verb spannan, meaning "to stretch, extend, or connect". This directly reflects the action of stretching the hand to measure the unit.

Span Conversion Formulas

To Meter:

1 span = 0.2286 m
Example: 5 spans = 1.143 meters

To Kilometer:

1 span = 0.000229 km
Example: 5 spans = 0.001143 kilometers

To Hectometer:

1 span = 0.002286 hm
Example: 5 spans = 0.01143 hectometers

To Decimeter:

1 span = 2.286 dm
Example: 5 spans = 11.43 decimeters

To Centimeter:

1 span = 22.86 cm
Example: 5 spans = 114.3 centimeters

To Millimeter:

1 span = 228.6 mm
Example: 5 spans = 1143 millimeters

To Inch:

1 span = 9 in
Example: 5 spans = 45 inches

To Foot:

1 span = 0.75 ft
Example: 5 spans = 3.75 feet

To Yard:

1 span = 0.25 yd
Example: 5 spans = 1.25 yards

To Mile:

1 span = 0.000142 mi
Example: 5 spans = 0.00071 miles

To Nautical Mile:

1 span = 0.000123 NM
Example: 5 spans = 0.000617 nautical miles

To Micrometer:

1 span = 228600 μm
Example: 5 spans = 1143000 micrometers

To Nanometer:

1 span = 228600000 nm
Example: 5 spans = 1143000000 nanometers

To Light Year:

1 span = 2.4162e-17 ly
Example: 5 spans = 1.2081e-16 light years

To Astronomical Unit:

1 span = 1.5281e-12 AU
Example: 5 spans = 7.6404e-12 astronomical units

To Parsec:

1 span = 7.4084e-18 pc
Example: 5 spans = 3.7042e-17 parsecs

To Angstrom:

1 span = 2286000000 Å
Example: 5 spans = 11430000000 angstroms

To Point (Typography):

1 span = 647.999592 pt
Example: 5 spans = 3239.997959 points

To Mil/Thou:

1 span = 9000 mil
Example: 5 spans = 45000 mils

To Fathom:

1 span = 0.125 fath
Example: 5 spans = 0.625 fathoms

To Furlong:

1 span = 0.001136 fur
Example: 5 spans = 0.005682 furlongs

To Link (Gunter's):

1 span = 1.136364 li
Example: 5 spans = 5.681818 links

To Pace:

1 span = 0.3 pace
Example: 5 spans = 1.5 paces

To Digit:

1 span = 12 digit
Example: 5 spans = 60 digits

To Cable Length:

1 span = 0.001234 cb
Example: 5 spans = 0.006172 cable lengths

To Ell:

1 span = 0.2 ell
Example: 5 spans = 1 ells

To Finger:

1 span = 2 finger
Example: 5 spans = 10 fingers

To Roman Mile:

1 span = 0.000154 m.p.
Example: 5 spans = 0.000772 Roman miles

To Stadion:

1 span = 0.001236 stadion
Example: 5 spans = 0.006178 stadia

To Chi (Chinese):

1 span = 0.685869 chi
Example: 5 spans = 3.429343 chi

To Shaku (Japanese):

1 span = 0.754455 shaku
Example: 5 spans = 3.772277 shaku

To Li (Chinese):

1 span = 0.000457 li
Example: 5 spans = 0.002286 li

To Toise:

1 span = 0.117291 toise
Example: 5 spans = 0.586455 toise

To Bolt:

1 span = 0.0075 bolt
Example: 5 spans = 0.0375 bolts

To Rope:

1 span = 0.0375 rope
Example: 5 spans = 0.1875 ropes

To Smoot:

1 span = 0.134328 smoot
Example: 5 spans = 0.671642 smoots

To Sajene:

1 span = 0.107143 sajene
Example: 5 spans = 0.535714 sajenes

To Ken:

1 span = 0.125743 ken
Example: 5 spans = 0.628713 ken

To Wa:

1 span = 0.1143 wa
Example: 5 spans = 0.5715 wa

To Vara:

1 span = 0.272727 vara
Example: 5 spans = 1.363636 varas

To Aln:

1 span = 0.384848 aln
Example: 5 spans = 1.924242 alnar

To Cubit (Royal/Egyptian):

1 span = 0.437094 cubit
Example: 5 spans = 2.185468 cubits

To Versta:

1 span = 0.000214 versta
Example: 5 spans = 0.001071 versts

To Arpent:

1 span = 0.00391 arpent
Example: 5 spans = 0.019548 arpents

To Ri (Japanese):

1 span = 0.000058 ri
Example: 5 spans = 0.000291 ri

To Klafter:

1 span = 0.120538 klafter
Example: 5 spans = 0.602689 klafter

To Yojana:

1 span = 0.000017 yojana
Example: 5 spans = 0.000085 yojanas

To Skein:

1 span = 0.002083 skein
Example: 5 spans = 0.010417 skeins

Convert Span

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Span Quick Info

span
Symbol:span
Category:Length
System:Various
Convert Span

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