Symbols of Inches and Feet
Quick answer: The symbol for feet is a single prime mark, ‘, and the symbol for inches is a double prime mark, “. So 5’7″ means 5 feet 7 inches, and 12” means 12 inches. The prime marks are written right after the number, with no space, and they save you from writing the words feet and inches every time.
Exact Meaning of ‘ and “
The foot symbol ‘ is called a prime, and the inch symbol ” is called a double prime. They come from a system once used for angles and lengths, where a single mark meant the first division and a double mark meant the second division. In length, one foot is divided into 12 inches, so the prime and double prime fit that pattern neatly.
| Written form | Meaning | In inches only |
|---|---|---|
| 1′ | 1 foot | 12 inches |
| 6″ | 6 inches | 6 inches |
| 5’7″ | 5 feet 7 inches | 67 inches |
| 6’2″ | 6 feet 2 inches | 74 inches |
| 3’6″ | 3 feet 6 inches | 42 inches |
To turn a feet-and-inches measurement into inches only, multiply the feet by 12 and add the inches. For 5’7″, that is 5 times 12, which is 60, plus 7, which is 67 inches. See how to convert feet to inches for more worked examples.
How to Read Sizes Like 5’7″
Read 5’7″ as five feet seven inches. The number before the single prime is always feet, and the number before the double prime is always inches. The order never changes: feet come first, then inches. A height written as 7″5 would be wrong, because it would mean seven inches and five of something else, not a height at all.
Heights are the most common place you will see this form. A person described as 5’7″ is 67 inches tall. A person described as 6’0″ is exactly six feet tall, with zero inches added. The zero is often kept in, so 6’0″ is clearer than 6′, which could be read as an estimate.
Room sizes, furniture, and screen sizes also use these symbols. A table listed as 3’6″ long is three feet six inches long. A shelf listed as 2′ wide is two feet wide. When only one unit is used, only one symbol appears: 24″ means 24 inches, and 8′ means 8 feet.
When to Use ‘ and When to Use “
Use ‘ only for feet, and ” only for inches. Never use ” for feet, and never use ‘ for inches. That rule sounds obvious, but it is easy to slip when typing quickly, especially because the double prime looks like a quotation mark on a keyboard.
In formal writing, write feet and inches in full the first time, then use symbols afterwards. In drawings and listings, symbols are standard.
Real-Life Examples of Feet and Inch Symbols
A door might be listed as 6’8″, which is six feet eight inches, or 80 inches in total. A television described as 55″ is 55 inches measured diagonally across the screen, not 55 feet, which would be enormous.
Common Mistakes With ‘ and “
One mistake is swapping the symbols, writing 5″7′ instead of 5’7″. That form has no standard meaning and will confuse a reader. Another mistake is leaving out the inch symbol when both units are present, writing 5’7 instead of 5’7″. The second number then looks like it has no unit.
People also confuse the double prime with a quotation mark in typing. On most keyboards, the same key produces a straight quotation mark, which is accepted as a double prime in everyday writing, but in careful typesetting, the prime marks are slightly slanted. For a website or a note, the keyboard characters are fine, as long as the order and the meaning are clear.
Another mistake is reading 5’7″ as 5.7 feet. It is not: 5 feet 7 inches is 5.58 feet, while 5.7 feet is about 5 feet 8 inches.
Frequently Asked Questions
What does 5’7″ mean?
Five feet seven inches, which is 67 inches in total, from 5 times 12, plus 7.
Which symbol is feet and which is inches?
A single prime, ‘, means feet, and a double prime, “, means inches.
How do I write six feet tall using symbols?
Write it as 6’0″, which means six feet and zero inches, or simply 6′ if the context is clear.
Is 5’7″ the same as 5.7 feet?
No. Five feet seven inches is 67 inches, or 5.58 feet in decimal form, while 5.7 feet is 68.4 inches, or about 5 feet 8 inches.
What does 55″ mean for a television?
It means the screen measures 55 inches diagonally, from one corner to the opposite corner, not 55 feet.