Span to Fathom Conversion Calculator: Free Online Tool
Convert spans to fathoms with our free online length converter.
Span to Fathom Calculator
How to Use the Calculator:
- Enter the value you want to convert in the 'From' field (Span).
- The converted value in Fathom will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Length category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Span to Fathom
Converting Span to Fathom involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Span = 0.125 fathomsExample Calculation:
Convert 10 spans: 10 × 0.125 = 1.25 fathoms
Disclaimer: For Reference Only
These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.
Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.
What is a Span and a Fathom?
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).
The Fathom (symbol fath) is a unit of length in the imperial and U.S. customary systems of measurement, defined as exactly 6 feet (ft). This is equivalent to 2 yards or 1.8288 meters (m). It is almost exclusively used in maritime contexts for measuring the depth of water.
Note: The Span is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Fathom belongs to the imperial/US customary system.
History of the Span and Fathom
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.
The word "fathom" originates from the Old English word fæthm, meaning "a pair of outstretched arms" or "embrace". Historically, the length was derived from the distance between the fingertips of a man's outstretched arms, a practical method for sailors measuring the length of a sounding line (a rope with a weight used to measure water depth) as they hauled it in. This naturally variable measure was eventually standardized to precisely 6 feet. For centuries, it was the primary unit for depth soundings on nautical charts and in maritime operations in English-speaking countries and beyond. While its official use has declined with metrication, it remains a significant unit in nautical tradition.
Common Uses for spans and fathoms
Explore the typical applications for both Span (imperial/US) and Fathom (imperial/US) to understand their common contexts.
Common Uses for spans
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.
Common Uses for fathoms
The fathom's use is strongly tied to the sea:
- Hydrography & Navigation: Measuring water depth (soundings) on nautical charts. Many charts, particularly older ones or those used in the US and UK, still use fathoms. Contour lines showing seabed depth are often called "fathom lines".
- Nautical Terminology: Used historically to measure the length of ropes and anchor cables (e.g., a "cable length" was often defined as 100 or 120 fathoms).
- Commercial Fishing: Sometimes used by fishermen to describe the length of nets or fishing lines, or the depth at which they are fishing.
- Literature & Figurative Language: Frequently appears in maritime literature (e.g., "full fathom five" from Shakespeare's The Tempest). Metaphorically, "to fathom" means to comprehend or get to the bottom of something complex.
- Historical Land Measurement: Very occasionally used in historical land surveying or mining contexts, but this was rare compared to its maritime use.
Frequently Asked Questions
Questions About Span (span)
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.
About Fathom (fath)
How many feet are in a fathom?
There are exactly 6 feet (ft) in 1 fathom.
How many meters are in a fathom?
One fathom is equal to exactly 1.8288 meters (m).
Is the fathom an SI unit?
No, the fathom is not an SI unit. It is part of the imperial and U.S. customary systems. The corresponding SI unit for length is the meter (m).
Is the fathom still commonly used today?
Its usage has decreased significantly due to the widespread adoption of the metric system in international shipping and hydrography. However, it remains common on nautical charts produced by countries like the United States and the United Kingdom, and it persists in recreational boating, commercial fishing communities, maritime tradition, and literature. Modern international charts increasingly use meters for depth soundings.
Where does the word 'fathom' come from?
The word originates from the Old English fæthm, which referred to the span of a person's outstretched arms. This distance was the practical basis for the original measurement used by sailors.
Conversion Table: Span to Fathom
| Span (span) | Fathom (fath) |
|---|---|
| 1 | 0.125 |
| 5 | 0.625 |
| 10 | 1.25 |
| 25 | 3.125 |
| 50 | 6.25 |
| 100 | 12.5 |
| 500 | 62.5 |
| 1,000 | 125 |
All Length Conversions
Other Units from Length
- Meter (m)
- Kilometer (km)
- Hectometer (hm)
- Decimeter (dm)
- Centimeter (cm)
- Millimeter (mm)
- Inch (in)
- Foot (ft)
- Yard (yd)
- Mile (mi)
- Nautical Mile (NM)
- Micrometer (μm)
- Nanometer (nm)
- Light Year (ly)
- Astronomical Unit (AU)
- Parsec (pc)
- Angstrom (Å)
- Point (Typography) (pt)
- Mil/Thou (mil)
- Furlong (fur)
- Link (Gunter's) (li)
- Pace (pace)
- Digit (digit)
- Cable Length (cb)
- Ell (ell)
- Finger (finger)
- Roman Mile (m.p.)
- Stadion (stadion)
- Chi (Chinese) (chi)
- Shaku (Japanese) (shaku)
- Li (Chinese) (li)
- Toise (toise)
- Bolt (bolt)
- Rope (rope)
- Smoot (smoot)
- Sajene (sajene)
- Ken (ken)
- Wa (wa)
- Vara (vara)
- Aln (aln)
- Cubit (Royal/Egyptian) (cubit)
- Versta (versta)
- Arpent (arpent)
- Ri (Japanese) (ri)
- Klafter (klafter)
- Yojana (yojana)
- Skein (skein)