Length · Unit Converter

Convert Fathom to Centiinch

Convert fathoms to centiinches instantly. 1 fathom = 7200 centiinch — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Centiinch to Fathom converter for the reverse conversion.

Written by Sunith Babu L, Ph.D., Lead Engineer Reviewed by Girish V Kulkarni Ph.D.
Length category 2 min read Published Last reviewed Updated

Units explained

Imperial / US Customary

Fathom

What is a 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.

Origin of the fathom

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.

Where it is used

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.

When and where it was developed

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.

Imperial / US Customary

Centiinch

What is a centiinch?

A centiinch is an Imperial unit of length equal to one hundredth of an inch (2.54×10⁻⁴ m). It is functionally identical to the caliber as a length unit but appears in different industrial contexts.

Origin of the centiinch

Derived from the inch via the metric-style prefix centi- (Latin centum, hundred). Standardised through the 1959 International Yard and Pound Agreement.

Where it is used

Centiinches occasionally appear in older engineering specifications and US-localised metric-pseudo notation. Most contemporary use prefers thousandths (mils) for sub-inch precision.

When and where it was developed

Standardised through the 1959 International Yard and Pound Agreement; rarely used in modern practice.

Fathom to Centiinch conversion formula

The relationship between fathoms and centiinches:

1 ftm = 7200 cin
1 cin = 0.0001388889 ftm

To convert fathoms to centiinches, multiply the value in fathoms by 7200. To reverse, multiply centiinches by 0.0001388889.

How to use this converter

Type a value into the calculator. The result in centiinches updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Centiinch to Fathom converter for the reverse direction.

Step-by-step: convert fathoms to centiinches

  1. Write down the value in fathoms (ftm).
  2. Multiply that value by the factor 7200.
  3. The product is the equivalent value in centiinches (cin).
  4. To reverse, multiply the centiinch value by 0.0001388889.

Worked examples

Example 1 — Convert 1 ftm to cin:
1 × 7200 = 7200 cin

Example 2 — Convert 100 ftm to cin:
100 × 7200 = 720000 cin

Real-world example — Sub-meter precision

A 0.001-fathom (1 mm) tolerance equals 1,000 centiinches — useful for surface-finish specs, where macro-scale dimensions are given in the larger unit but feature roughness in the smaller.

0.001 ftm × 7200 = 7.2 cin

Real-world example — Macro-to-micro scale comparison

2 fathoms of measurement converts to a very large number in centiinches — useful in materials science when comparing bulk-sample dimensions to feature-level surface specs.

2 ftm × 7200 = 14400 cin

Real-world example — Macroscopic to microscopic

One fathom equals a million centiinches. Optical engineers calculating coherence length compare macro-scale path lengths with micro-scale wavelength differences using exactly this conversion.

1 ftm × 7200 = 7200 cin

Fathom to Centiinch conversion table

Standard reference values for converting fathoms to centiinches:

Fathom [ftm]Centiinch [cin]
0.0172
0.1720
17200
214400
321600
428800
536000
1072000
20144000
30216000
40288000
50360000
100720000
5003600000
10007200000

Frequently asked questions

How many centiinches is 1 fathom?
1 fathom equals 7200 centiinch.
How do I convert fathoms to centiinches?
Multiply the value in fathoms by 7200 to get centiinches.
How do I convert centiinches back to fathoms?
Multiply the value in centiinches by 0.0001388889, or use the Centiinch to Fathom converter.
How many centiinches is 100 fathoms?
100 fathoms equals 720000 centiinches, because 100 × 7200 = 720000.

Convert Fathom to other length units

Show all Fathom conversions

Sources & references

Conversion factor (1 ftm = 7200 cin) verified against the following authoritative sources:

Results are provided for general reference. Verify critical measurements against an authoritative standard.