A fathom is six feet.
Fathoms to Nautical miles Converter — ftm to nmi
Convert Fathom (ftm) to Nautical mile (nmi) using the exact conversion factor (1 fathom = 0.000987473 nautical mile). See the formula, worked examples, conversion table, history, and common uses.
Fathoms to Nautical miles converter
Converter
Length Converter
Convert SI, imperial, US customary, astronomical, scientific, and historical length units.
Context values
Some unit families need one extra value for a physically accurate result.
A nautical mile is exactly 1,852 meters.
Result = input x 1.8288 / 1852.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Fathoms to Nautical miles
Fathom and Nautical mile both measure length. Specifically: A fathom is six feet, and a nautical mile is exactly 1,852 meters.
Formula
nautical miles = fathoms × 0.00098747300216
This factor comes from each unit's defined relationship to the category's base unit: 1 fathom equals 1.8288 base units, and 1 nautical mile equals 1852 base units, so dividing one by the other gives the direct fathom-to-nautical mile factor of 0.00098747300216.
Simple example
1 ftm × 0.0009874730022 = 0.000987473 nmi
1 fathom = 0.000987473 nautical miles.
Real-world example
10 ftm × 0.0009874730022 = 0.00987473 nmi
10 fathoms = 0.00987473 nautical miles.
Conversion table
| Fathom (ftm) | Nautical mile (nmi) |
|---|---|
| 1 ftm | 0.000987473 nmi |
| 5 ftm | 0.004937365 nmi |
| 10 ftm | 0.00987473 nmi |
| 21.0975 ftm | 0.0208332117 nmi |
| 42.195 ftm | 0.0416664233 nmi |
| 100 ftm | 0.0987473002 nmi |
Reverse conversion: Nautical mile to Fathom
0.000987473 nmi × 1012.685914 = 0.9999999978 ftm
0.000987473 nautical miles = 0.9999999978 fathoms.
fathoms = nautical miles × 1012.68591426
For a page dedicated to this direction, see Nautical mile to Fathom.
Understanding the Fathom (ftm)
A fathom is six feet.
Understanding the Nautical mile
Nautical mile (nmi) measures distance. The international nautical mile is defined as exactly 1,852 meters, standardized in 1929. It is classified as a Non-SI unit accepted for use with SI (maritime/aviation).
Where it's used: Used internationally in maritime navigation and aviation.
Uses of the Nautical mile today
- Marine and aviation distance and navigation
- Basis for the knot (nautical miles per hour)
History of the Nautical mile
The nautical mile was historically defined as one minute of latitude along a meridian, directly tying sea navigation to the Earth's geometry, which made it practical for chart-based navigation using a ship's known latitude. The International Hydrographic Bureau standardized it at exactly 1,852 meters in 1929, a value close to the traditional latitude-based definitions used by different countries.
Historical origin. Nautical mile was not the invention of a single named person; it developed through the process described above.
Nautical mile — sources
- BIPM SI Brochure — Non-SI units accepted for use with SI — Lists the nautical mile among accepted non-SI units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many nautical miles are in 1 fathom?
1 fathom equals 0.000987473 nautical miles, using the exact defined conversion factor rather than an estimate.
How do I convert fathom to nautical mile?
Multiply the fathom value by 0.0009874730022. The converter above does this instantly to whatever precision you set.
How do I convert nautical mile back to fathom?
Use the reverse factor: 1 nautical mile equals 1,012.685914 fathoms. You can also use the swap control in the converter above to flip the direction instantly.
What is a fathom?
Fathom (ftm) is a unit of length.
What is a nautical mile?
Nautical mile (nmi) measures distance. The international nautical mile is defined as exactly 1,852 meters, standardized in 1929. It is classified as a Non-SI unit accepted for use with SI (maritime/aviation).
Is the fathom to nautical mile conversion exact?
Yes. The international nautical mile is defined as exactly 1,852 meters, standardized in 1929. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.