Convert feet to fathoms easily.
1 ft ÷ 6 = 0.167 ftm
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Ever tried picturing how deep 100 feet of water is? If you’re a sailor, diver, or just someone who loves nautical trivia, you’ve probably heard the term “fathom.” But how does it relate to feet—the unit we use for height, room dimensions, and mountain elevations? Let’s unravel this maritime mystery together. Whether you’re checking the depth of a shipwreck or decoding old sailing maps, converting feet to fathoms is simpler than tying a bowline knot (and way less slippery).
Unit definitions
What is a foot (ft)?
A foot is one of the oldest units of length, tracing back to ancient civilizations. It’s roughly based on the average adult male’s foot length, though standardization took centuries. Today, 1 international foot equals exactly 0.3048 meters. You’ll see it everywhere: road signs, blueprints, and even weather reports for snow depth.
- Symbol: ft
- Common uses: Height measurement, real estate, aviation altitude
- Definition: 1 ft = 12 inches = 0.3048 meters
What is a fathom (ftm)?
The fathom is the ocean’s favorite unit. Originally defined as the span of a person’s outstretched arms (about 6 feet), it became crucial for sailors measuring anchor ropes or water depth. Fun fact: The word “fathom” comes from the Old English “fæthm,” meaning “embracing arms.” It’s still used in nautical charts and fishing regulations today.
- Symbol: ftm
- Common uses: Maritime depth, cable length, fishing regulations
- Definition: 1 ftm = 6 feet = 1.8288 meters
Conversion formula
To convert feet to fathoms, divide the number of feet by 6. Why? Because one fathom is literally six feet. Here’s the formula:
Fathoms = Feet ÷ 6
For example:
- 18 feet ÷ 6 = 3 fathoms
- 42 feet ÷ 6 = 7 fathoms
If math isn’t your first mate, use our calculator above. Just type the feet value, and it’ll spit out fathoms faster than a cannonball sinks.
Example calculations
Example 1: You’re reading a novel where a character dives 24 feet underwater. How many fathoms is that?
24 ÷ 6 = 4 fathoms. That’s like jumping off a two-story building into the sea!
Example 2: A fishing regulation states lobster traps must be in waters ≥ 30 fathoms deep. What’s that in feet?
30 × 6 = 180 feet. That’s deeper than the Statue of Liberty is tall (151 feet from base to torch).
Conversion tables
Feet to fathoms
| Feet | Fathoms |
|---|---|
| 6 | 1 |
| 12 | 2 |
| 18 | 3 |
| 24 | 4 |
| 30 | 5 |
| 36 | 6 |
| 42 | 7 |
| 48 | 8 |
| 54 | 9 |
| 60 | 10 |
Fathoms to feet
| Fathoms | Feet |
|---|---|
| 1 | 6 |
| 2 | 12 |
| 3 | 18 |
| 4 | 24 |
| 5 | 30 |
| 6 | 36 |
| 7 | 42 |
| 8 | 48 |
| 9 | 54 |
| 10 | 60 |
Historical background
The foot’s history is a wild ride. Ancient Egyptians used a “royal cubit” (~1.715 feet), while the Roman foot was slightly shorter at 11.6 inches. Chaos reigned until 1959, when teh U.S., U.K., and others agreed on the “international foot” (12 inches = 0.3048 meters).
Fathoms, meanwhile, kept sailors sane. Before sonar, crews lowered lead-weighted ropes marked in fathoms to check depth. If the rope reached “by the mark 5” (5 fathoms), they knew it was safe to anchor. Shakespeare even referenced fathoms in The Tempest: “Full fathom five thy father lies.”
Interesting facts?
- Titanic’s Depth: The Titanic rests at 12,500 feet—about 2,083 fathoms.
- Pirate Lingo: Pirates used “fathom” to mean “understand,” as in “I can’t fathom yer plan.”
- Aviation vs. Nautical: Pilots measure altitude in feet, not fathoms. A plane at 30,000 ft is 5,000 fathoms high!
- Global Usage: Myanmar and Liberia still use feet alongside meters. Fathoms? Mostly the U.S. and U.K.
- Deepest Point: The Mariana Trench is 36,070 feet deep—6,011.67 fathoms. That’s 7,000 times taller than your fridge.
FAQ
Fathoms remain popular in maritime contexts for measuring water depth, especially in countries using imperial units. They provide a quick reference for sailors—6 feet is easier to visualize than decimal-based meters in emergency situations.
One fathom equals 6 feet or 1.8288 meters. If you’re standing in a pool, that’s roughly the height of two average adults stacked head-to-foot.
Absolutely! Since 1 fathom is 6 feet and 1 foot is 0.3048 meters, multiply fathoms by 1.8288 to get meters. Our calculator above can handle this too by switching units.
Pilots worldwide use feet for altitude, not fathoms. Fathoms are strictly nautical, while feet dominate aviation, engineering, and everyday measurements in countries like the U.S.
Fathoms are primarily used in the U.S. and U.K. for nautical purposes. Most other countries adopted meters post-1950s, but you’ll still hear 'fathom' in older maritime documents globally.