Inch Symbol (″) and Foot Symbol (′): How to Type Them Correctly

Measurements in feet and inches are traditionally written with two small marks: ′ for feet and ″ for inches, so that 5 feet 10 inches is 5′ 10″. Those marks are the prime and double prime, not quotation marks, though straight quotes have stood in for them since typewriters. The problem today is autocorrect: type 10” in Word and you get 10” with a curly closing quote, which is wrong and looks wrong. This guide explains the right characters and how to type them everywhere.

Quick answer

The four look-alike characters

The prime marks are slightly slanted and taper; curly quotes curl. Straight quotes are vertical. Once you see the difference, a curly inch mark stands out immediately.

Windows

There is no classic Alt code for the primes because they are outside the Windows-1252 code page. Use one of these:

• Word and Outlook: type 2033 and press Alt + X for ″, or 2032 then Alt + X for ′.
• Any app: press Win + ., open the Symbols tab, and search “prime”.
• Character Map: find U+2032 and U+2033 under Advanced view with Unicode enabled.

Mac

Open the Character Viewer with Control + Command + Space, search “prime”, and double-click ″ or ′. If you type measurements often, add a text replacement under System Settings → Keyboard → Text Replacements so that, for example, ;in becomes ″. The Option key layer has no prime symbols on the US layout.

Word and Google Docs: stopping the curly quote

If you are happy to use straight quotes, the only obstacle is smart quotes.

Word

1. Type 10". Word turns it into 10”.
2. Press Ctrl + Z once. Word reverts just the smart quote, leaving a straight “.

To turn the feature off, open File → Options → Proofing → AutoCorrect Options → AutoFormat As You Type and untick “Straight quotes” with “smart quotes”. Existing curly quotes are not changed; use Find and Replace with the same setting off to fix them.

Google Docs

Docs applies smart quotes too. Undo with Ctrl + Z right after typing, or turn them off under Tools → Preferences by unticking Use smart quotes. Docs also accepts the true primes through Insert → Special characters (search “prime”).

Excel and Sheets

Cells do not apply smart quotes, so a straight quote types normally. Use a custom number format to show units without typing them: Format Cells → Custom with 0"″" displays 72 as 72″ while keeping the number, and 0' "′" 0"″" style formats can be built for feet and inches from separate columns. Paste ″ and ′ into the format string from the top of this page.

Phones

On iPhone and Android, hold the “ key on the symbol page to see alternatives; the prime marks are usually not among them, so copy ″ and ′ from this page and add them as text replacements (Settings → General → Keyboard → Text Replacement on iOS; Gboard personal dictionary on Android).

HTML and code

In HTML a straight quote inside an attribute must be written as ", which is one more reason to use the real prime for measurements in web content.

Style notes

• Write 5′ 10″ or 5’10” with no space before either mark. A thin space between the two values is optional.
• Do not mix curly quotes with primes in one document.
• In engineering drawings and CAD software the double prime is standard; many CAD programs insert it automatically when the unit format is set to architectural.
• The same marks denote arc minutes and seconds (48° 30′ 15″) and, in math, derivatives (f′, f″, f‴).

Troubleshooting

• The inch mark still curls after turning smart quotes off. The setting only affects new typing. Use Find and Replace: search for ” and replace with “ or ″.
• ″ shows as a box. The font lacks the glyph; switch to Arial, Calibri, Segoe UI or Times New Roman, all of which include the primes.
• Alt+X converts the wrong thing. Select only the four-digit code before pressing Alt+X if it follows a number, since Word may read 102033 as one code.

Frequently asked questions