Subscript Generator
Convert text to Unicode subscript for chemical formulas and math indices: H2O becomes H₂O. Paste-anywhere plain text. Free, instant.
About this tool
Convert characters into real Unicode subscript: H2O becomes H₂O and CO2 becomes CO₂. The output is plain text, not formatting, so it pastes intact into chat apps, social posts, spreadsheets, YouTube titles, and anywhere else rich-text subscript is unavailable.
All ten digits and the basic math symbols have subscript forms, along with a limited set of letters (a e h i j k l m n o p r s t u v x). Characters without a Unicode subscript form pass through unchanged.
Common uses
- Write chemical formulas like H₂O, CO₂, and C₆H₁₂O₆ in plain text.
- Write math indices like x₁, x₂ in messages and documents.
- Label variables in code comments or plain-text notes.
Automate via API
The same conversion is available as a REST endpoint for scripts, pipelines, and backends:
curl -X POST https://payloadly.com/api/v1/tools/subscript-generator \ -H "Content-Type: text/plain" \ -H "X-Api-Key: YOUR_API_KEY" \ --data-binary @input.txt
Frequently asked questions
Is my data uploaded to a server?
No. This tool runs entirely in your browser using JavaScript, and there are no ads on the page. Nothing you paste or drop here is uploaded, logged, or stored, and you can verify that yourself: open your browser's developer tools and watch the Network tab while you convert (no requests leave the page), or disconnect from the internet after the page loads and keep working.
Why do fewer letters work in subscript than superscript?
Unicode added subscript letters mainly for phonetic transcription, and only 16 made it in; there is no subscript b, c, d, or any capital. Digits and math symbols are complete, which covers chemical formulas and indices, the two things subscript is usually needed for.
Is there a size limit or a fee?
The browser tool is free with no signup and comfortably handles files up to tens of megabytes (limited by your device's memory). For automated or bulk processing inside your own scripts and pipelines, use the paid REST API.
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