Fathom to Span Converter
Convert Fathom (ftm) to Span (span) instantly. 1 ftm = 8 span.
Length Converter
31 units available
1 ftm = 8 span
Formula:
span = ftm × 8With your value: 1 ftm = 8 span
How big is that?
Everyday references on a logarithmic scale, all expressed in fathom so you can sanity-check the result.
Other Fathom to Span conversions
Fathom to Span Conversion Table
| Fathom (ftm) | Span (span) |
|---|---|
| 0.5 | 4 |
| 1 | 8 |
| 2 | 16 |
| 5 | 40 |
| 10 | 80 |
| 15 | 120 |
| 20 | 160 |
| 25 | 200 |
| 50 | 400 |
| 100 | 800 |
| 250 | 2,000 |
| 500 | 4,000 |
| 1000 | 8,000 |
Span to Fathom Conversion Table
| Span (span) | Fathom (ftm) |
|---|---|
| 0.5 | 0.0625 |
| 1 | 0.125 |
| 2 | 0.25 |
| 5 | 0.625 |
| 10 | 1.25 |
| 15 | 1.875 |
| 20 | 2.5 |
| 25 | 3.125 |
| 50 | 6.25 |
| 100 | 12.5 |
| 250 | 31.25 |
| 500 | 62.5 |
| 1000 | 125 |
Where these values come from
Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.
Fathom (ftm)
Length
Traceable to the metre, defined by fixing the speed of light in vacuum at 299 792 458 m/s. Imperial lengths derive from the 1959 international yard (0.9144 m exactly).
Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)
Bureau International des Poids et Mesures · Reviewed 2026-07-01
Span (span)
Length
Traceable to the metre, defined by fixing the speed of light in vacuum at 299 792 458 m/s. Imperial lengths derive from the 1959 international yard (0.9144 m exactly).
Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)
Bureau International des Poids et Mesures · Reviewed 2026-07-01
How to Convert Fathom to Span
To convert from Fathom (ftm) to Span (span), multiply the value by 8.
Formula: span = ftm × 8
Reverse: ftm = span × 0.125
Step-by-Step Example
- Start with your value in Fathom. For example: 5 ftm
- Multiply by the conversion factor: 5 x 8
- The result is: 40 span
About Fathom
The fathom equals 6 feet (1.8288 m) and is the traditional unit for water depth on nautical charts.
Fun Fact: The word comes from the Old English "fæðm", the span of a man's outstretched arms.
Common uses: sounding depth, nautical charts, diving.
About Span
The span (span) is a unit of distance and length. One span equals 0.2286 metres. UnitConvertLab converts it against every other length unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
Common uses: length calculations, engineering and science, education.
Frequently Asked Questions
How many Span are in 1 Fathom?
There are exactly 8 Span in 1 Fathom. This means the conversion factor from Fathom to Span is 8.
What is the formula to convert Fathom to Span?
The formula to convert Fathom to Span is: span = ftm × 8. For example, to convert 10 Fathom to Span, you would multiply 10 by 8.
What is a Fathom?
The fathom equals 6 feet (1.8288 m) and is the traditional unit for water depth on nautical charts.
What is a Span?
The span (span) is a unit of distance and length. One span equals 0.2286 metres. UnitConvertLab converts it against every other length unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
What are the common uses of Fathom?
The Fathom is commonly used in sounding depth, nautical charts, diving.
Related Length Conversions
Cite this page
UnitConvertLab. (2026). Fathom to Span converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/fathom-to-span