To convert miles to fathoms, multiply by 880. That factor is the whole relationship: both units measure length, so the conversion is a proportion with no offset and no substance-specific constant.
Six feet, the traditional depth unit on marine charts. The statute mile: 5,280 feet, used for road distance in the US, UK and a handful of others.
The mil and the millimetre are not the same thing and are out by a factor of about forty. A mil is one thousandth of an inch — 0.0254 mm — and a spec sheet that quotes film thickness in mils means the small unit. British drawings write the same size as "thou". The tables underneath give both a plain step-by-step lookup and a list of real quantities expressed in fathoms, so you can sanity-check whether your answer is a plausible size.
The formula
miles- The amount you are converting, in miles
880- The exact number of fathoms in one mile
fathoms- The converted result
How it works, step by step
- Enter the value in miles.
- It is multiplied by 880, the exact factor between the two units.
- The answer is shown in fathoms, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
The Eiffel Tower: 0.205 mi in fathoms
The Eiffel Tower comes to about 0.205 mi. Multiplying by the factor: 0.205 × 880 = 180.4 ftm. Dividing the answer back by 880 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
Earth’s diameter: 7920 mi in fathoms
Earth’s diameter comes to about 7920 mi. Multiplying by the factor: 7920 × 880 = 6.9696e+06 ftm. Dividing the answer back by 880 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
How to read your score
Frequently asked questions
How many fathoms are in one mile?
Exactly 880. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert miles to fathoms?
fathoms = miles × 880. Reversed, miles = fathoms ÷ 880, which is the same as multiplying by 0.00113636363636.
Which is the bigger unit, the mile or the fathom?
The mile. One mile equals 880 fathoms.
What does this quantity actually measure?
Both units measure length. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a mile?
The statute mile: 5,280 feet, used for road distance in the US, UK and a handful of others.
What is a fathom?
Six feet, the traditional depth unit on marine charts.
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Is there a quick way to do mi to ftm in my head?
Plenty of people do this in their head: multiply by 900 instead of using the exact factor 880. At 100 that shortcut gives 90,000 fathoms, off by 2000 fathoms or about 2.27%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Miles to fathoms reference tables
| Miles | Fathoms |
|---|---|
| 0.5 mi | 440 ftm |
| 1 mi | 880 ftm |
| 2 mi | 1760 ftm |
| 3 mi | 2640 ftm |
| 5 mi | 4400 ftm |
| 10 mi | 8800 ftm |
| 20 mi | 17,600 ftm |
| 25 mi | 22,000 ftm |
| 50 mi | 44,000 ftm |
| 75 mi | 66,000 ftm |
| 100 mi | 88,000 ftm |
| 250 mi | 220,000 ftm |
| 500 mi | 440,000 ftm |
| 1000 mi | 880,000 ftm |
| 5000 mi | 4.4e+06 ftm |
Exact factor: 1 mile = 880 fathoms.
| Quantity | mi | ftm |
|---|---|---|
| A credit card’s long edge | 5.319e-05 mi | 0.04681 ftm |
| A door height | 0.001263 mi | 1.111 ftm |
| An Olympic pool | 0.03107 mi | 27.34 ftm |
| The Eiffel Tower | 0.2051 mi | 180.4 ftm |
| A marathon | 26.22 mi | 2.307e+04 ftm |
| Earth’s diameter | 7918 mi | 6.967e+06 ftm |
Published reference values, converted with the same factor this page uses.