Double Struck Font Generator

Type a line and copy it back in double-struck letters and digits, the blackboard bold of a maths lecture.

Double Struck Font Generator

Sample. Type or paste your own to replace it.

Double-struck 18 characters

ℤ𝕠𝕟𝕖 𝟚: ℕ𝕠 ℙ𝕒𝕣𝕜𝕚𝕟𝕘

Every letter and number here has a character in this set.

Same text, other styles

  • Bold 18 characters𝐙𝐨𝐧𝐞 𝟐: 𝐍𝐨 𝐏𝐚𝐫𝐤𝐢𝐧𝐠

More options

Use these for fun, not for anything that matters. Screen readers read many of these characters badly or skip them, search cannot find them, and some apps strip them or show empty boxes.

All 72 characters: tap one to copy it

72 characters in 5 groups.

With a keyboard: Tab goes into the table once, the arrow keys move inside it, and Enter copies.

The seven older capitals 7

Capitals 19

Small letters 26

Digits 10

Slanted, Greek and sum 10

Next step Add a sign from 160 math symbolsTry Fraktur, another maths alphabet

How it works

This double struck font generator swaps each letter and digit for one with a doubled stroke, the style mathematicians call blackboard bold. Seven of its 72 characters predate the rest. Some apps strip or block these characters, and screen readers may read them badly.

Read the full guide

One chalk row, one bold row

The large card sets your line in Double-struck, digits included. Punctuation stays as typed. Bold sits below, because bold is what the doubled stroke stood for: Wikipedia's article on blackboard bold records that lecturers doubled strokes to write bold symbols in chalk.

Seven capitals that came first

C, H, N, P, Q, R and Z were in Unicode by June 1993 as symbols in their own right: ℕ natural numbers, ℤ integers, ℚ rationals, ℝ reals, ℂ complex numbers. The full alphabet followed in March 2001 and left those seven slots empty. The old seven count as one UTF-16 unit each, the rest as two.

Tips
  • The table gives each capital's meaning in mathematics. Double-struck capital H is the quaternions, H for Hamilton, in Wikipedia's table.
  • Five slanted letters sit last in the table, copy-only. Unicode notes that Double-struck italic small d is sometimes used for the differential.
  • Unicode's chapter says these alphabets are for mathematics, not styled prose. A search will not find a word written in them.

Questions and answers

Is this a math font generator?

For one alphabet, yes. Double-struck is the style mathematics uses for sets of numbers, and this page lists all of it. The other maths alphabets, bold, script and Fraktur among them, are on the font generator, which sets one line in 21.

Is double-struck the same as blackboard bold?

Yes. Blackboard bold is the mathematicians' name. Double-struck is Unicode's, and Wikipedia's article traces it to typewriters, where typing a character over itself for a bolder look was called double-striking. The article dates the chalk version to the late 1950s or early 1960s.

How do I get ℝ in LaTeX?

Wikipedia's article gives \mathbb{R}, from the amssymb package, and notes that its blackboard bold face covers capital letters only. Unicode also has small letters and digits, which is why this page can set a whole sentence and LaTeX's command cannot.

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Browse Text styles

All 72 characters

The seven older capitals 7

  • Double-struck capital C U+2102. Stands for capital C. Unicode's names list calls it the set of complex numbers. Slot U+1D53A of the 2001 alphabet stays empty.
  • Double-struck capital H U+210D. Stands for capital H. Unicode gives it no meaning. Wikipedia's table of blackboard bold has it as the quaternions, the H standing for Hamilton. Slot U+1D53F of the 2001 alphabet stays empty.
  • Double-struck capital N U+2115. Stands for capital N. Unicode's names list calls it natural number. Wikipedia's table adds that the set may or may not include zero. Slot U+1D545 of the 2001 alphabet stays empty.
  • Double-struck capital P U+2119. Stands for capital P. Unicode gives it no meaning. Wikipedia's table has it as projective space, a probability or the prime numbers. Slot U+1D547 of the 2001 alphabet stays empty.
  • Double-struck capital Q U+211A. Stands for capital Q. Unicode's names list calls it the set of rational numbers. Wikipedia's table has the Q standing for quotient. Slot U+1D548 of the 2001 alphabet stays empty.
  • Double-struck capital R U+211D. Stands for capital R. Unicode's names list calls it the set of real numbers. Slot U+1D549 of the 2001 alphabet stays empty.
  • Double-struck capital Z U+2124. Stands for capital Z. Unicode's names list calls it the set of integers. Wikipedia's table has the Z standing for German Zahl, number. Slot U+1D551 of the 2001 alphabet stays empty.
Show all 72 characters (65 more)

Capitals 19

  • Mathematical double-struck capital A U+1D538. Stands for capital A. In Wikipedia's table of blackboard bold: affine space, or the ring of adeles.
  • Mathematical double-struck capital B U+1D539. Stands for capital B. In Wikipedia's table of blackboard bold: sometimes a ball or a boolean domain.
  • Mathematical double-struck capital D U+1D53B. Stands for capital D. In Wikipedia's table of blackboard bold: the unit disk in the complex plane.
  • Mathematical double-struck capital E U+1D53C. Stands for capital E. In Wikipedia's table of blackboard bold: the expected value of a random variable, or Euclidean space.
  • Mathematical double-struck capital F U+1D53D. Stands for capital F. In Wikipedia's table of blackboard bold: a field, often a finite one.
  • Mathematical double-struck capital G U+1D53E. Stands for capital G. In Wikipedia's table of blackboard bold: a Grassmannian or a group.
  • Mathematical double-struck capital I U+1D540. Stands for capital I. In Wikipedia's table of blackboard bold: the closed unit interval.
  • Mathematical double-struck capital J U+1D541. Stands for capital J. Wikipedia's table of blackboard bold lists no use for it in mathematics.
  • Mathematical double-struck capital K U+1D542. Stands for capital K. In Wikipedia's table of blackboard bold: a field, the K standing for German Körper.
  • Mathematical double-struck capital L U+1D543. Stands for capital L. In Wikipedia's table of blackboard bold: the Lefschetz motive.
  • Mathematical double-struck capital M U+1D544. Stands for capital M. In Wikipedia's table of blackboard bold: sometimes the monster group.
  • Mathematical double-struck capital O U+1D546. Stands for capital O. In Wikipedia's table of blackboard bold: the octonions.
  • Mathematical double-struck capital S U+1D54A. Stands for capital S. In Wikipedia's table of blackboard bold: a sphere.
  • Mathematical double-struck capital T U+1D54B. Stands for capital T. In Wikipedia's table of blackboard bold: the circle group.
  • Mathematical double-struck capital U U+1D54C. Stands for capital U. Wikipedia's table of blackboard bold lists no use for it in mathematics.
  • Mathematical double-struck capital V U+1D54D. Stands for capital V. In Wikipedia's table of blackboard bold: a vector space.
  • Mathematical double-struck capital W U+1D54E. Stands for capital W. In Wikipedia's table of blackboard bold: the whole numbers.
  • Mathematical double-struck capital X U+1D54F. Stands for capital X. In Wikipedia's table of blackboard bold: occasionally an arbitrary metric space.
  • Mathematical double-struck capital Y U+1D550. Stands for capital Y. Wikipedia's table of blackboard bold lists no use for it in mathematics.

Small letters 26

  • Mathematical double-struck small a U+1D552. Stands for small a in double-struck.
  • Mathematical double-struck small b U+1D553. Stands for small b in double-struck.
  • Mathematical double-struck small c U+1D554. Stands for small c in double-struck.
  • Mathematical double-struck small d U+1D555. Stands for small d in double-struck.
  • Mathematical double-struck small e U+1D556. Stands for small e in double-struck.
  • Mathematical double-struck small f U+1D557. Stands for small f in double-struck.
  • Mathematical double-struck small g U+1D558. Stands for small g in double-struck.
  • Mathematical double-struck small h U+1D559. Stands for small h in double-struck.
  • Mathematical double-struck small i U+1D55A. Stands for small i in double-struck. Wikipedia's table records that it is sometimes used for the imaginary unit.
  • Mathematical double-struck small j U+1D55B. Stands for small j in double-struck.
  • Mathematical double-struck small k U+1D55C. Stands for small k in double-struck. In Wikipedia's table it represents a field.
  • Mathematical double-struck small l U+1D55D. Stands for small l in double-struck.
  • Mathematical double-struck small m U+1D55E. Stands for small m in double-struck.
  • Mathematical double-struck small n U+1D55F. Stands for small n in double-struck.
  • Mathematical double-struck small o U+1D560. Stands for small o in double-struck.
  • Mathematical double-struck small p U+1D561. Stands for small p in double-struck.
  • Mathematical double-struck small q U+1D562. Stands for small q in double-struck.
  • Mathematical double-struck small r U+1D563. Stands for small r in double-struck.
  • Mathematical double-struck small s U+1D564. Stands for small s in double-struck.
  • Mathematical double-struck small t U+1D565. Stands for small t in double-struck.
  • Mathematical double-struck small u U+1D566. Stands for small u in double-struck.
  • Mathematical double-struck small v U+1D567. Stands for small v in double-struck.
  • Mathematical double-struck small w U+1D568. Stands for small w in double-struck.
  • Mathematical double-struck small x U+1D569. Stands for small x in double-struck.
  • Mathematical double-struck small y U+1D56A. Stands for small y in double-struck.
  • Mathematical double-struck small z U+1D56B. Stands for small z in double-struck.

Digits 10

  • Mathematical double-struck digit eight U+1D7E0. Stands for 8 in double-struck.
  • Mathematical double-struck digit five U+1D7DD. Stands for 5 in double-struck.
  • Mathematical double-struck digit four U+1D7DC. Stands for 4 in double-struck.
  • Mathematical double-struck digit nine U+1D7E1. Stands for 9 in double-struck.
  • Mathematical double-struck digit one U+1D7D9. Stands for 1 in double-struck. In Wikipedia's table: the indicator function, the identity matrix or a tautology.
  • Mathematical double-struck digit seven U+1D7DF. Stands for 7 in double-struck.
  • Mathematical double-struck digit six U+1D7DE. Stands for 6 in double-struck.
  • Mathematical double-struck digit three U+1D7DB. Stands for 3 in double-struck.
  • Mathematical double-struck digit two U+1D7DA. Stands for 2 in double-struck. In Wikipedia's table: the interval category, in category theory.
  • Mathematical double-struck digit zero U+1D7D8. Stands for 0 in double-struck. In Wikipedia's table: a contradiction or falsity, in the algebra of logical propositions.

Slanted, Greek and sum 10

  • Double-struck capital gamma U+213E. A double-struck Greek capital gamma. Unicode gives it no meaning. Tap to copy it.
  • Double-struck capital pi U+213F. A double-struck Greek capital pi. Unicode gives it no meaning. Tap to copy it.
  • Double-struck italic capital D U+2145. A slanted double-struck D. Unicode's names list: sometimes used for the differential. Nothing you type becomes it. Tap to copy it.
  • Double-struck italic small d U+2146. A slanted double-struck d. Unicode's names list: sometimes used for the differential. Nothing you type becomes it. Tap to copy it.
  • Double-struck italic small e U+2147. A slanted double-struck e. Unicode's names list: sometimes used for the natural exponent. Tap to copy it.
  • Double-struck italic small i U+2148. A slanted double-struck i. Unicode's names list: sometimes used for the imaginary unit. Tap to copy it.
  • Double-struck italic small j U+2149. A slanted double-struck j. Unicode's names list: sometimes used for the imaginary unit. Tap to copy it.
  • Double-struck n-ary summation U+2140. A double-struck summation sign, the only operator in the style. Tap to copy it.
  • Double-struck small gamma U+213D. A double-struck Greek small gamma. Unicode gives it no meaning. Tap to copy it.
  • Double-struck small pi U+213C. A double-struck Greek small pi. Unicode gives it no meaning. Tap to copy it.

How this list was compiled: All 72 rows were generated by a script from the Unicode Character Database, version 18.0.0 (https://www.unicode.org/Public/18.0.0/ucd/UnicodeData.txt), and the script stops unless every name is the one expected and every row carries a <font> decomposition. Ages come from https://www.unicode.org/Public/18.0.0/ucd/DerivedAge.txt and blocks from https://www.unicode.org/Public/18.0.0/ucd/Blocks.txt. The script counts 97 character names that hold the word DOUBLE-STRUCK. This list is the 72 that are not Arabic: 26 capitals, 26 small letters, ten digits and ten copy-only characters from Letterlike Symbols (five slanted letters, four Greek letters and a summation sign). Seven capitals, C H N P Q R and Z, live in Letterlike Symbols with age 1.1, the oldest age that file records, and the script confirms that their seven slots in the run from U+1D538 are unassigned. The meanings Unicode itself gives (the set of complex numbers, natural number, the set of rational numbers, the set of real numbers, the set of integers, and the notes on the slanted letters) are read from https://www.unicode.org/Public/18.0.0/ucd/NamesList.txt by the script. Every other meaning is from the usage table of https://en.wikipedia.org/wiki/Blackboard_bold, downloaded as wikitext, and the script stops unless the words quoted are in the table cell for that code point; the rows say "Wikipedia's table" so the reader knows whose claim it is. That article dates the first blackboard bold letters in Unicode to version 1.0 (1991); the age file starts at 1.1, so the page says they were in Unicode by June 1993. Left out on purpose: the 25 Arabic mathematical double-struck letters U+1EEA1 to U+1EEBB, which nobody types on a Latin keyboard. Section 22.2 of the core specification (https://www.unicode.org/versions/Unicode18.0.0/core-spec/chapter-22/) is the source for the holes and for Table 22-2, which gives double-struck Latin letters and digits. Release dates are from https://www.unicode.org/history/publicationdates.html (1.1 in June 1993, 3.1 in March 2001, 3.2 in March 2002, 4.1 on 31 March 2005). All checked on 2026-09-20. Names are the official ones in sentence case. Licence: own work (facts from the Unicode Character Database, Unicode License v3, and from Wikipedia, CC BY-SA 4.0, restated in our own words)