What double struck text is
Double struck letters look as if they were traced twice, with a thin gap left inside the thick strokes. The style began on chalkboards. A teacher who wanted a bold letter could not press harder with chalk, so they drew an extra line next to the first one. Printers later copied the look, and it became standard in mathematics, where it is often called blackboard bold.
You have probably seen ℝ for the real numbers, ℕ for the natural numbers or ℤ for the integers. Outside maths the style has a clean, modern feel, a little like a neon sign or an outlined logo, which makes it popular for usernames, headings and bios.
How to use the double struck text generator
- Type into the Your text box. Letters and numbers both work.
- The large result at the top shows your text in Double Struck.
- Press Copy and paste the result wherever you need it.
- Press Clear to empty the box and try another word.
If you want to compare styles, scroll down to More styles. Every other style on the site is listed with your text already converted, and each row has its own Copy button.
How it works
Unicode treats double struck letters as separate characters, not as a font setting. Most of them live in the Mathematical Alphanumeric Symbols block, starting with the capital 𝔸 at U+1D538. The digits have their own run from 𝟘 (U+1D7D8) to 𝟡.
Seven capitals are the exception. ℂ, ℍ, ℕ, ℙ, ℚ, ℝ and ℤ were already in Unicode’s Letterlike Symbols block because they name common number sets, so the maths block leaves those slots empty. The generator knows about the gaps and uses the older characters for those letters. The result is a complete alphabet, even though it comes from two places.
As with other styled text, the characters keep their look wherever they go, because the shape is part of the character. Under Unicode normalization (NFKC), each one also maps back to its plain letter, which is how tools like the Unicode to text converter can undo it.
Examples
These results come from the generator on this page.
| You type | Result |
|---|---|
| Double Struck | 𝔻𝕠𝕦𝕓𝕝𝕖 𝕊𝕥𝕣𝕦𝕔𝕜 |
| Level 99 | 𝕃𝕖𝕧𝕖𝕝 𝟡𝟡 |
| Real numbers R | ℝ𝕖𝕒𝕝 𝕟𝕦𝕞𝕓𝕖𝕣𝕤 ℝ |
| CHZNPQR | ℂℍℤℕℙℚℝ |
The last row is made entirely of the seven borrowed capitals.
Where to use double struck letters
- Maths and science notes written in plain text, such as a chat message or a forum post about sets of numbers
- Gaming names where a crisp outline reads well next to a level or rank number
- Bio headings and section titles in a profile
- Logos and wordmarks in a quick plain text mock-up
- Scoreboards and lists where outlined digits help numbers stand apart from the text around them
For a heavier look with the same structure, try the bold text generator. For a darker, medieval feel, the gothic font generator uses the Fraktur alphabet from the same Unicode block.
Tips and limits
Check the weight. Because seven capitals come from an older block, some fonts draw them a little thicker or thinner than the rest. In a word like “CHAMPION”, the C, H and N may stand out slightly. Try a few spellings and see which looks best on your device.
Small sizes blur. The hollow middle needs room. In a small font, double struck letters can look like ordinary bold or turn fuzzy. Keep them for names and headings rather than long paragraphs.
Screen readers. Many screen readers read these as “mathematical double-struck capital D” and so on, letter by letter, or skip them. Do not put the only copy of key details in this style.
Search. A search for “Level 99” will not match “𝕃𝕖𝕧𝕖𝕝 𝟡𝟡” on most sites. If people need to find you by name, keep a plain version somewhere they can search.
Font support. Current versions of Android, iOS, Windows and macOS include these characters. Older devices may show empty boxes, so test on another phone if it matters.
Related tools
The Unicode text converter shows the code point of every character, which is handy if you want to see exactly which double struck letters came from the older block. It also lists every other style on the site.