Unit symbols pack a measurement label into a single character. Most of this set comes from the CJK Compatibility block, where squared units such as ㎎ ㎖ ㎚ ㎒ ㎾ ㏈ and ㎇ each fill one fullwidth cell. They were added in Unicode 1.1 (1993) so text from older East Asian character sets could convert to Unicode without losing anything, and Unicode treats them as compatibility characters rather than the recommended way to write units. Beside them sit the script ℓ often used for liters, the per mille ‰ and per ten thousand ‱ signs, the numero sign №, the apothecary ounce ℥, the pound weight sign ℔, and the dedicated ohm Ω and angstrom Å signs. People paste them into spec tables, nutrition notes, ham radio and audio posts, and Japanese style product labels where a tidy single-cell unit looks neat. For the degree sign, Celsius and the common metric squares, the temperature set is the better page.
Unit Symbols للنسخ
What normalization does to these characters
Every squared unit here carries a compatibility decomposition, so NFKC normalization spells it out in ordinary letters: ㎎ becomes mg, ㎒ becomes MHz and ㎉ becomes kcal. A few results are surprising. ㎢ turns into km2 with a plain 2, because the superscript is folded as well, and ㏗ becomes PH in capitals rather than pH. ㎍ and ㎛ normalize to the Greek mu, not to the micro sign. The ohm Ω (U+2126) and angstrom Å (U+212B) go further: their decomposition is canonical, so even the gentler NFC form replaces them with the Greek capital omega and the Latin A with ring. Unicode recommends those ordinary letters for new text.
When a single-cell unit helps and when it hurts
In a narrow table column or a vertical Japanese label, ㎖ or ㎑ keeps a value and its unit locked together so a line break cannot split them. They also make a compact flourish in a gaming bio, such as 40㎳ ping. The cost is findability. A shop listing that says 500㎎ will only match a search for 500 mg if the search system normalizes text, and screen readers may announce the character by its name, square mg, instead of saying milligrams. For anything a customer or a search engine needs to read, type the plain letters and keep these for decoration.
الأسئلة الشائعة
Is ‱ a real unit sign?▼
Yes. ‱ is the per ten thousand sign, U+2031, and it means parts per ten thousand. One ‱ equals 0.01 percent, the same size as a basis point in finance, so 25‱ is a quarter of a percent. Its sibling ‰ is per mille, parts per thousand, common in salinity figures and in European blood alcohol limits.
Why is ℓ used for liters?▼
ℓ is the script small l, U+2113. Because a lowercase l is easy to confuse with the digit 1, some countries and older textbooks write liters as ℓ, and the squared units ㎖ ㎗ ㎘ are even built on it in their decomposition. The official SI symbols are l or L, so ℓ is a style choice rather than a standard. NFKC turns it into a plain l.
Should I copy the ohm sign or the Greek omega?▼
For most writing, use the Greek capital omega Ω (U+03A9). The ohm sign Ω (U+2126) is canonically equivalent to it, so many apps silently swap it during normalization anyway, and fonts usually draw the two the same. The ohm sign is here for completeness and for legacy data that already contains it.
