Subscript Generator

Write chemical formulas and indices that keep their subscripts when you paste them into a chat, a slide, a spreadsheet cell or a social post: H₂O, CO₂, C₆H₁₂O₆, SO₄²⁻, x₁. Formula mode knows the element symbols, so it lowers only the digits that belong in a subscript and raises ionic charges; underscore mode lowers whatever follows _, and you can also convert all of the text.

How to use this tool

1. Type the formula or text: H2O, Ca(OH)2, SO4^2- or x_1.
2. Choose formula mode for chemistry, underscore mode for maths indices, or all text.
3. Copy the Unicode result, or the HTML version for a web page.
4. Check the note: characters with no subscript form stay normal.

Formula

In a formula, digits right after an element symbol or a closing bracket → subscript; a final + or − (with its number) → superscript charge

Element symbols are checked against all 118 elements, so words like Hello or A4 are left alone (but a word that is also a valid formula, such as B12, is converted). Leading numbers are coefficients and stay normal (2H₂O), as do numbers after a hydrate dot (CuSO₄·5H₂O). For a charge without ^, two or more digits before the sign mean “last digit is the charge” (SO42- → SO₄²⁻); one digit is the charge of a single-element ion (Fe3+ → Fe³⁺) but a subscript in a polyatomic ion (NH4+ → NH₄⁺). Unicode subscripts exist for the digits, + − = ( ) and the letters a e h i j k l m n o p r s t u v x only.

Example

The sample “C6H12O6 + 6O2 → 6CO2 + 6H2O” becomes C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O: the coefficients 6 stay full size, while every digit after an element symbol is lowered. In HTML the first term is C₆H₁₂O₆.