How to type Double Prime
To type Double Prime (″), press Alt + 8243 on Windows, holding Alt while typing the digits on the numeric keypad, or write ″ in HTML. On any system you can copy it from this page, or enter its codepoint U+2033 directly: Ctrl+Shift+U then 2033 on Linux, or 2033 then Alt+X in Microsoft Word.
Double Prime
- Copy it
- Unicode
- U+2033
- Windows
- Alt + 8243 needs regedit
| Where | Shortcut | How |
|---|---|---|
| Windows | Alt + 8243 | Above 255, so Windows will not accept it as typed. Copy the character instead. |
| Mac | N/A | Press the keys together. |
| HTML | ″ | Paste this into HTML source. |
| Unicode | U+2033 | DOUBLE PRIME |
Symbols related to Double Prime
The Unicode code chart points from ″ to " and ”, and the rest are filed under prime in CLDR, the keyword list Unicode publishes alongside the names.
Other math symbols
″ lives in the General Punctuation block (U+2000-U+206F), dashes, quotation marks, spaces and reference marks used across languages. Within Unicode it is classified as Po, a punctuation mark. Its bidirectional class makes it a European number terminator, so it sits beside a number without breaking its direction.
What happens to ″ in a search box
″ is a compatibility character: Unicode says it can be rewritten as ′′, two separate characters. Anything that normalises text to NFKC before comparing it does exactly that, which is why ″ pasted into a search field, a URL slug or a username can come back as ′′ and match text that never contained ″ at all. NFC, the form this site uses, leaves it alone.
What Double Prime is used for
In mathematical notation ″ is an ordinary symbol: it carries no special spacing and sits in an expression the way a letter does, standing for a thing rather than doing something to the things around it. That is the classification unicode-math gives it, and it is what decides how the symbol is set: $\dprime$ in LaTeX, in maths mode rather than in a sentence.
What Unicode says about Double Prime
The standard recognises ″ under another name as well: seconds, inches. That is a formal alias, not a nickname, which is why it turns up in other people's documentation for the same codepoint.
The code chart points from ″ to Quotation Mark, Right Double Quote, modifier letter double prime (U+02BA), ditto mark (U+3003) and double prime quotation mark (U+301E). These are the characters the standard thinks you might have meant instead, which makes them the ones worth checking when Double Prime looks nearly right but not quite.
How Double Prime behaves in software
″ is East Asian Ambiguous: one column in a Western locale and two in a CJK one. That is why a table that lines up on your machine can break on somebody else's, with no change to the text at all. It carries no direction of its own, so in a line that mixes English with Arabic or Hebrew it takes the direction of the text around it rather than forcing one.
What people ask about Double Prime
What is f prime of x mean?
″ is DOUBLE PRIME, encoded at U+2033. It is distinct from quotation mark (U+0022) and modifier letter double prime (U+02BA), which the chart lists beside it precisely because they are confused for one another.
Every way to write Double Prime
| Form | Value |
|---|---|
| Codepoint | U+2033 |
| Decimal | 8243 |
| UTF-8 bytes | E2 80 B3 |
| UTF-16 bytes | 20 33 |
| HTML entity | ″ |
| HTML numeric | ″ or ″ |
| CSS | \2033 |
| JavaScript | \u2033 |
| Python | \u2033 |
| URL-encoded | %E2%80%B3 |
| LaTeX, in maths mode | $\dprime$ |
| SVG | 2033.svg · (SIL Open Font License) |
If ″ arrives as ″
Its three UTF-8 bytes E2 80 B3 are being read one at a time as Windows-1252. The text is undamaged; the reader has to be told it is UTF-8.