Short answer: The correct mark for feet is the prime ′ and for inches the double prime ″ — not an apostrophe or quote. In Word, type 2032 then Alt + X for ′ (2033 for ″). On Windows, hold Alt and type 8242 (′) or 8243 (″). On a Mac or phone, copy them below.
Tap to copy prime marks
Height, lumber, coordinates, angles: the correct symbols for feet and inches are the prime ′ and double prime ″, not the apostrophe and quotation mark most people reach for. So 5′10″ is right; 5’10” is a keyboard-limited substitute. Here’s how to type the real marks everywhere. This is part of the Punctuation hub.
Quick reference
| Symbol | Means | Windows (keypad) | Word | HTML | Unicode |
|---|---|---|---|---|---|
| ′ | Feet, arcminutes | Alt + 8242 | 2032 then Alt + X | ′ | U+2032 |
| ″ | Inches, arcseconds | Alt + 8243 | 2033 then Alt + X | ″ | U+2033 |
| ‴ | Triple prime (lignes) | Alt + 8244 | 2034 then Alt + X | ‴ | U+2034 |
Prime vs apostrophe — the distinction that matters
The prime looks almost like an apostrophe or straight quote, but they’re different characters with different jobs. The apostrophe (‘) and quotation mark (“) are punctuation; the prime (′) and double prime (″) are unit marks that sit slightly slanted and upright. Using apostrophes and quotes for measurements is common because of keyboard limits, but it isn’t correct in careful or professional writing — architecture, engineering and typesetting all use true primes.
The bigger trap is curly “smart” quotes. Word processors auto-convert straight marks into curly ones (‘ → ‘ and ” → “), which curl toward the text — exactly wrong for a measurement. If you’ve ever typed 5’10” and watched it become 5’10”, that’s smart quotes. The fix is to insert real primes, or disable the auto-replacement (see below). More on that difference: straight vs curly quotes.
Windows
Alt codes (numeric keypad, Num Lock on): Alt + 8242 for ′, Alt + 8243 for ″. These are Unicode values and work in Unicode-aware apps.
No numeric keypad? Use Win + . and search prime, or use Word’s Alt + X method below. If an Alt code returns the wrong character, you’re on the top-row numbers — see why Alt codes don’t work.
Word (the most reliable route)
Type the Unicode hex and press Alt + X: 2032 → ′, 2033 → ″, 2034 → ‴. Or go Insert → Symbol → More Symbols and find them in the General Punctuation subset.
To stop Word curling your straight marks into smart quotes, go to File → Options → Proofing → AutoCorrect Options → AutoFormat As You Type and untick “Straight quotes” with “smart quotes”. (In Google Docs: Tools → Preferences → uncheck “Use smart quotes”.) Then a plain " stays straight — though the true ″ is still the correct mark.
Mac
macOS has no dedicated Option shortcut for prime marks. Press Control + Command + Space to open the Character Viewer, search prime, and double-click ′ or ″. If you use them often, save a text replacement (System Settings → Keyboard → Text Replacements) mapping something like ft' to ′.
iPhone, Android and the web
Phones: there’s no prime on the default keyboard — copy ′ and ″ from the tool above, or save them as text replacements for repeat use.
Google Docs: Insert → Special characters and search prime.
Chromebook / Linux: press Ctrl + Shift + U, type 2032 (′) or 2033 (″), then Enter.
HTML / web: the named entity for the prime is ′ (lowercase p) and for the double prime ″ (uppercase P); numeric forms are ′ and ″. The Unicode code points are U+2032 and U+2033.
How to write it correctly
- Height / length: prime after the feet, double prime after the inches, no space — 5′10″, 6′2″.
- Coordinates and angles: degree, then prime, then double prime — 40°26′46″ N. (For the degree mark, see the degree symbol.)
- Maths: the prime also marks a derivative, f′(x), or a related variable, x′ — same character.
Troubleshooting
| Problem | Fix |
|---|---|
| My inch mark curled into ″ → “ | Smart quotes converted it. Insert the real ″, or disable smart-quote auto-replacement. |
| Alt + 8242 does nothing | Num Lock off, top-row numbers used, or a non-Unicode app. Use the keypad, or Word’s 2032 + Alt + X. |
| Prime shows as a box ▯ | The font lacks the glyph. Switch to a common font (Arial, Times New Roman). More: symbol showing as a box. |
| It just looks like an apostrophe | Many body fonts render it subtly; it’s still the correct character semantically. Check the code point is U+2032/U+2033. |
Frequently asked questions
What is the difference between the prime ′ and an apostrophe?
The prime (′, U+2032) and double prime (″, U+2033) are unit marks for feet/inches and minutes/seconds, drawn slightly slanted and upright. The apostrophe (‘) and quotation mark (“) are punctuation. Apostrophes and quotes are common stand-ins because of keyboard limits, but primes are the correct marks in professional writing.
How do you type the feet ′ and inches ″ symbols on Windows?
In Microsoft Word, type 2032 then press Alt + X for ′, and 2033 then Alt + X for ″. Elsewhere, hold Alt and type 8242 (′) or 8243 (″) on the numeric keypad with Num Lock on.
How do you type prime symbols on a Mac?
There’s no dedicated Option shortcut. Press Control + Command + Space to open the Character Viewer, search “prime”, and double-click ′ or ″. For frequent use, add a text replacement in System Settings.
Why does my inch mark turn curly (″ → “)?
Your app’s smart-quotes feature is auto-converting straight marks into curly ones, which is wrong for measurements. Insert the real double prime ″, or turn off smart quotes in AutoCorrect (Word) or Tools → Preferences (Google Docs).
How do you write feet and inches together, like a height?
Put the prime after the feet and the double prime after the inches, with no space: 5′10″ or 6′2″. For coordinates, add the degree first, as in 40°26′46″ N.
What are the Unicode code points and HTML entities for prime and double prime?
The prime is U+2032 (HTML ′, or ′) and the double prime is U+2033 (HTML ″, or ″). The triple prime is U+2034.
Recap
- Feet → ′ (Word: 2032 then Alt + X; Windows: Alt + 8242).
- Inches → ″ (Word: 2033 then Alt + X; Windows: Alt + 8243).
- Write height as 5′10″ — real primes, not 5’10”.
- Mac / phone → copy them or use a text replacement.
Written by Igor R.. Tested on Windows 11, macOS, iOS, Android, ChromeOS, Word and Google Docs. Last updated July 2026. Symbol code points follow the Unicode Standard.