Convert Fathom to Kilometer
Convert fathoms to kilometers instantly. 1 fathom = 0.0018288 kilometer — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Kilometer 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.
Kilometer
A kilometer is a metric unit of length equal to one thousand meters. It is the standard unit for measuring road distances, geographic distances, and other large-scale measurements in metric countries.
The kilometer was defined alongside the meter in 1795 using the standard SI prefix kilo- (from Greek chilioi, "thousand"), denoting one thousand units.
Kilometers are used worldwide (except the United States and a few others) for road signage, geographic distance, athletic events, and scientific distances at planetary scale. Speed limits in most countries are given in km/h.
Adopted 1795 in France as part of the original metric system; the kilometer became the global standard for road and geographic distance through the 19th and 20th century metric adoption.
Fathom to Kilometer conversion formula
The relationship between fathoms and kilometers:
To convert fathoms to kilometers, multiply the value in fathoms by 0.0018288. To reverse, multiply kilometers by 546.8066491689.
How to use this converter
Type a value into the calculator. The result in kilometers updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Kilometer to Fathom converter for the reverse direction.
Step-by-step: convert fathoms to kilometers
- Write down the value in fathoms (ftm).
- Multiply that value by the factor 0.0018288.
- The product is the equivalent value in kilometers (km).
- To reverse, multiply the kilometer value by 546.8066491689.
Worked examples
Example 1 — Convert 1 ftm to km:
1 × 0.0018288 = 0.0018288 km
Example 2 — Convert 100 ftm to km:
100 × 0.0018288 = 0.18288 km
Real-world example — Metric distance scale-up
One thousand fathoms equals one kilometer — 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 × 0.0018288 = 1.8288 km
Real-world example — Imperial mile arithmetic
5,280 fathoms equals exactly one kilometer. 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 × 0.0018288 = 9.656064 km
Real-world example — Imperial yard-to-mile scale
1,760 fathoms equals exactly one kilometer. 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 × 0.0018288 = 3.218688 km
Fathom to Kilometer conversion table
Standard reference values for converting fathoms to kilometers:
| Fathom [ftm] | Kilometer [km] |
|---|---|
| 0.01 | 1.8288e-5 |
| 0.1 | 0.00018288 |
| 1 | 0.0018288 |
| 2 | 0.0036576 |
| 3 | 0.0054864 |
| 4 | 0.0073152 |
| 5 | 0.009144 |
| 10 | 0.018288 |
| 20 | 0.036576 |
| 30 | 0.054864 |
| 40 | 0.073152 |
| 50 | 0.09144 |
| 100 | 0.18288 |
| 500 | 0.9144 |
| 1000 | 1.8288 |
Frequently asked questions
How many kilometers is 1 fathom?
How do I convert fathoms to kilometers?
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How many kilometers 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 = 0.0018288 km) 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.