Subscript Generator: Type H₂O and CO₂ Online

Example

Before

H2O and CO2

After

H₂O ₐₙd CO₂

Common uses

Chemical formulas like H₂O, CO₂, and C₆H₁₂O₆, and math or science notation such as x₁ and x₂.

Which letters are available

Unicode only includes subscript digits, math signs, and the lowercase letters a, e, h, i, j, k, l, m, n, o, p, r, s, t, u, v, and x. Other letters are left unchanged.

Subscript in documents

Word uses Ctrl+= for subscript formatting (Cmd+= on a Mac), Google Docs uses Ctrl+, (Cmd+, on a Mac), and HTML uses the <sub> element. Use this generator where formatting isn’t available: chat, social posts, spreadsheet cells, slide titles, and file names.

Examples

Water is H₂O, carbon dioxide CO₂, glucose C₆H₁₂O₆, and sulfuric acid H₂SO₄. In math, sequences are written a₁, a₂, …, aₙ, and logarithms with a base as log₂ x. Chemists also write ions with a superscript charge, so combine this with the superscript generator for SO₄²⁻.

Frequently asked questions

Why aren’t all letters converted?

Unicode only has subscript forms of some lowercase letters (a, e, h, i, j, k, l, m, n, o, p, r, s, t, u, v, x), and no subscript capitals.

Will subscript text work in Excel?

Yes. The characters are ordinary text, so they display in a cell and survive copying, unlike Excel’s font effect.

Is H₂O searchable?

Not always. Search engines may not match H₂O to H2O, so include the plain version where people will search.