How to Type Chemistry Symbols: H₂O, CO₂, Ions & Arrows

Short answer: In Word, type the formula, then use Ctrl + = for subscripts (the 2 in H₂O) and Ctrl + Shift + = for superscripts (charges like Na⁺). In Google Docs it’s Ctrl + , and Ctrl + . For plain text (social media, chat, code), use the actual Unicode subscript characters — copy them from the tool below.

Tap to copy a chemistry symbol

Chemical formulas need small lowered numbers (H₂O, CO₂, C₆H₁₂O₆) and small raised charges (Na⁺, SO₄²⁻), plus a few special arrows. There are two completely different ways to get them, and choosing the right one is the whole trick. This guide is part of the Math symbols hub.

The key idea: formatting vs characters

In a document (Word, Google Docs, PowerPoint, Excel), use subscript/superscript formatting. The “2” stays a normal digit that’s just styled smaller and lower. This is best for anything you’ll print, search or share as a file — it reads correctly and stays editable.
In plain text (Instagram, WhatsApp, X, code, plain email), there’s no formatting, so you need the actual Unicode subscript/superscript characters — a separate “₂” that is its own character. You copy these in.

Get this right and everything else follows. The rest of this guide covers both routes per platform.

Quick reference

What	Symbols	Unicode	Windows Alt
Subscript digits	₀ ₁ ₂ ₃ ₄ ₅ ₆ ₇ ₈ ₉	U+2080–2089	Alt + 8320–8329
Superscript digits	⁰ ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹	U+2070, 00B9, 00B2, 00B3, 2074–2079	² = Alt+0178
Superscript + / −	⁺ ⁻	U+207A / U+207B	Alt+8314 / 8315
Subscript + / −	₊ ₋	U+208A / U+208B	Alt+8330 / 8331
Equilibrium arrow	⇌	U+21CC	Alt+8652
Yields arrow	→	U+2192	Alt+26

Word and Outlook

The formatting method is fastest and cleanest:

Subscript: press Ctrl + =, type the number, then press Ctrl + = again to turn it off. So H, Ctrl + =, 2, Ctrl + =, O gives H₂O.
Superscript: press Ctrl + Shift + = for charges and exponents — Na, Ctrl + Shift + =, + gives Na⁺.

For a fully stacked, semantic formula, use the equation editor (Alt + =), where _ makes a subscript and ^ a superscript — SO_4^{2-} renders SO₄²⁻. If you’d rather insert the actual Unicode characters, type the hex and press Alt + X (2082 → ₂).

Google Docs

Use the built-in formatting shortcuts: Ctrl + , (comma) for subscript and Ctrl + . (period) for superscript — press again to toggle off. So typing CO, Ctrl + , , 2 gives CO₂. You can also use Format → Text → Subscript / Superscript, or Insert → Special characters to drop in a Unicode subscript character.

Excel and Google Sheets

In Excel, select the digit inside the cell, open Format Cells → Font, and tick Subscript — good for a label like CO₂ shown in a cell. (Because formatting applies to text, this works for display, not for values used in calculations.) In Google Sheets, which lacks a subscript format, paste the Unicode character ₂ instead, or use =CHAR() with the code.

Windows — plain-text characters

When you’re in a plain-text field (social posts, chat, code comments), formatting isn’t available, so type the Unicode characters directly: hold Alt and use the numeric keypad — Alt + 8322 gives ₂, 8323 ₃, 8326 ₆; superscripts include Alt + 0178 ², Alt + 8314 ⁺, Alt + 8315 ⁻. Num Lock must be on. If a code returns the wrong character, you’re on the number row — see why Alt codes don’t work.

Mac

In Word or Pages, the formatting shortcuts are Cmd + = (subscript) and Cmd + Shift + = (superscript); Pages also offers Format → Font → Baseline. For the plain Unicode characters, open the Character Viewer with Control + Command + Space and search subscript two (or the number), then double-click — handy when you’re pasting a formula into a plain-text app.

iPhone and Android

Phone keyboards don’t offer subscript formatting, so the only reliable route is the Unicode characters: copy ₂ ₃ ⁺ ⁻ from the tool above, then paste into your formula (H₂O). For formulas you write often, save a text replacement (iPhone: Settings → General → Keyboard → Text Replacement; Android: Personal dictionary) — for example map h2o to H₂O.

Chromebook and Linux

Google Docs on a Chromebook uses the same Ctrl + , / Ctrl + . formatting shortcuts. For a raw Unicode character in other apps, press Ctrl + Shift + U, type the hex (2082 for ₂), then Enter. On Linux, the same Ctrl + Shift + U method works in most GTK/IBus apps, or use the Characters / gucharmap app.

HTML, CSS and code

On the web you again have two options:

Semantic markup: wrap the number in  or  — H2O and Na+. This is the correct, accessible way for web pages, and it works in any font.
Unicode characters: use the actual subscript character where markup isn’t possible (a plain-text field, a page title, an alt attribute): ₂ gives ₂, ₃ ₃, ⁺ ⁺. In CSS use content:"\2082"; in JavaScript "\u2082".

For a document that will be read by screen readers, prefer / — they’re announced more reliably than the standalone characters.

Reaction arrows, ion charges and other symbols

The rest of the chemistry toolkit:

Yields → the reaction arrow is the right arrow → (U+2192); ⇌ (U+21CC, Alt + 8652) is the equilibrium arrow. A gas produced is often marked ↑ and a precipitate ↓. More arrow options: arrow symbols.
Ion charges combine super- and subscripts: Na⁺, Cl⁻, Fe³⁺, and SO₄²⁻ (subscript 4, then superscript 2 and minus). Use a real minus (the superscript ⁻, U+207B) rather than a hyphen.
Δ (delta) marks heat or change — the Greek capital delta Δ (U+0394); see the pi symbol for typing Greek letters.
Degrees for temperature use the degree sign ° — see the degree symbol.

Troubleshooting

Problem	Fix
Subscript 2 pastes as a full-size 2	You copied a formatted (not Unicode) subscript into a plain-text field. Use the Unicode character ₂ there.
Alt + 8322 does nothing	Num Lock off, or top-row numbers used. Use the numeric keypad.
Formula loses subscripts in email/social	Those are plain-text fields — switch to the Unicode characters (₂), not formatting.
Charge looks like a hyphen	Use the superscript minus ⁻ (U+207B), not the keyboard hyphen.
Subscript/superscript letters missing	Unicode only has a few subscript letters (ₐ ₑ ₒ ₓ …); for others, use formatting or `<sub>`.
Character shows as a box ▯	The font lacks the glyph. Switch to a common Unicode font (Arial, Segoe UI). More: symbol showing as a box.

Frequently asked questions

How do you type H₂O and CO₂ in Word or Google Docs?

Use subscript formatting. In Word, press Ctrl + = , type the number, then Ctrl + = again to turn it off. In Google Docs, press Ctrl + , (comma) for subscript. So H, subscript on, 2, subscript off, O gives H₂O.

How do you type subscripts in plain text like social media?

Plain-text fields have no formatting, so you need the actual Unicode subscript characters (₀–₉). Copy them and paste them into your formula — for example H₂O — or on Windows type Alt + 8322 for ₂ on the numeric keypad.

How do you type ion charges like Na⁺ or SO₄²⁻?

Use superscript for the charge. In a document, apply superscript formatting (Ctrl + Shift + = in Word) to the + or −; in plain text, use the Unicode superscript characters ⁺ and ⁻. A charge like SO₄²⁻ combines a subscript 4 with a superscript 2 and minus.

What is the difference between subscript formatting and the Unicode subscript character?

Formatting keeps a normal digit but styles it smaller and lower — best for documents, and it stays searchable and editable. The Unicode subscript character (₂) is a separate character with its own code point — needed in plain text where formatting isn’t available, like social media or code.

How do you type the equilibrium arrow ⇌?

Its Unicode code point is U+21CC. On Windows hold Alt and type 8652 on the numeric keypad; in Word, type 21CC and press Alt + X. You can also copy it. The plain reaction arrow is → (U+2192).

What are the Unicode code points for subscript and superscript numbers?

Subscript digits are U+2080 (₀) to U+2089 (₉). Superscripts are U+2070 (⁰), U+00B9 (¹), U+00B2 (²), U+00B3 (³) and U+2074–U+2079 (⁴–⁹). The superscript plus and minus are U+207A (⁺) and U+207B (⁻).

Recap

Documents → formatting: Word Ctrl + = / Ctrl + Shift + =; Docs Ctrl + , / Ctrl + .
Plain text → Unicode characters (₂ = Alt + 8322), copied in.
Web →  /  for pages; Unicode characters for plain fields.
Charges & arrows → ⁺ ⁻, →, ⇌ (Alt + 8652), ↑ ↓.

Written by Igor R.. Tested on Windows 11, macOS, iOS, Android, ChromeOS, Linux, Word and Google Docs. Last updated July 2026. Symbol code points follow the Unicode Standard.