Convert Fathom to League
Convert fathoms to leagues instantly. 1 fathom = 0.0003787879 league — use the live calculator, the exact formula, a conversion table and worked examples. Also check the League to Fathom converter for the reverse conversion.
Units explained
Fathom
A fathom is an Imperial unit of length equal to 6 feet or exactly 1.8288 meters. It is used almost exclusively for measuring water depth in maritime contexts.
The fathom derives from the Old English word fæthm, meaning "the embracing arms" — the distance between the fingertips of a person's outstretched arms. Standardized at 6 feet in English maritime tradition.
Fathoms are used in nautical depth charts, scuba diving, oceanography, and maritime literature. Despite metrication efforts, fathoms remain common in English-language nautical charts and recreational diving.
Old English origin (predating 1066); standardized at 6 feet by English maritime tradition; fixed at 1.8288 m exactly via the 1959 International Yard and Pound Agreement.
League
A league is an Imperial unit of length equal to 3 miles (about 4.83 km). It is one of the oldest distance units in English usage, historically representing the distance a person could walk in one hour.
The English league derives from the ancient Roman leuga via medieval English customary practice. Standardised at 3 statute miles in English law.
Leagues appear in historical English literature ('seven-league boots'), maritime navigation (a nautical league is 3 nautical miles), and traditional distance descriptions. Modern usage is largely literary.
Medieval English customary origin; standardised at 3 miles; became exact via the 1959 International Yard and Pound Agreement.
Fathom to League conversion formula
The relationship between fathoms and leagues:
To convert fathoms to leagues, multiply the value in fathoms by 0.0003787879. To reverse, multiply leagues by 2640.
How to use this converter
Type a value into the calculator. The result in leagues updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the League to Fathom converter for the reverse direction.
Step-by-step: convert fathoms to leagues
- Write down the value in fathoms (ftm).
- Multiply that value by the factor 0.0003787879.
- The product is the equivalent value in leagues (lea).
- To reverse, multiply the league value by 2640.
Worked examples
Example 1 — Convert 1 ftm to lea:
1 × 0.0003787879 = 0.0003787879 lea
Example 2 — Convert 100 ftm to lea:
100 × 0.0003787879 = 0.0378787879 lea
Real-world example — Imperial mile arithmetic
5,280 fathoms equals exactly one league. American hikers tracking elevation gain in the smaller unit but trail length in the larger one use this constant every time they read a topographic map.
5280 ftm × 0.0003787879 = 2 lea
Real-world example — Imperial yard-to-mile scale
1,760 fathoms equals exactly one league. American athletes and surveyors use this conversion to translate distances quoted in the smaller imperial unit into recognizable fractions of the larger geographic one.
1760 ftm × 0.0003787879 = 0.6666666667 lea
Real-world example — Metric distance scale-up
One thousand fathoms equals one league — the running distance for a 1K race or the standard metric kilometre-scale step. The simple thousand-fold conversion is the most-used metric distance translation.
1000 ftm × 0.0003787879 = 0.3787878788 lea
Fathom to League conversion table
Standard reference values for converting fathoms to leagues:
| Fathom [ftm] | League [lea] |
|---|---|
| 0.01 | 3.787879e-6 |
| 0.1 | 3.787879e-5 |
| 1 | 0.0003787879 |
| 2 | 0.0007575758 |
| 3 | 0.0011363636 |
| 4 | 0.0015151515 |
| 5 | 0.0018939394 |
| 10 | 0.0037878788 |
| 20 | 0.0075757576 |
| 30 | 0.0113636364 |
| 40 | 0.0151515152 |
| 50 | 0.0189393939 |
| 100 | 0.0378787879 |
| 500 | 0.1893939394 |
| 1000 | 0.3787878788 |
Frequently asked questions
How many leagues is 1 fathom?
How do I convert fathoms to leagues?
How do I convert leagues back to fathoms?
How many leagues is 100 fathoms?
Popular length unit conversions
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Metric / SI (7 units)
Imperial / US Customary (26 units)
Nautical (1 units)
Sources & references
Conversion factor (1 ftm = 0.0003787879 lea) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.