Unicode bold text
Hello World 2026 becomes 𝐇𝐞𝐥𝐥𝐨 𝐖𝐨𝐫𝐥𝐝 𝟐𝟎𝟐𝟔: 14 letters and digits swapped for Unicode Mathematical Bold characters, so the style travels with the text into bios, captions and titles. Bold text can be turned back too. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Text
- Hello World 2026
- Calculation mode
- Encode
- Result
- 𝐇𝐞𝐥𝐥𝐨 𝐖𝐨𝐫𝐥𝐝 𝟐𝟎𝟐𝟔
- Direction
- encode
- Mapped
- 14
- Unmapped count
- 1
Unicode Mathematical Bold turns ordinary Latin letters and digits into look-alike styled characters from the Mathematical Alphanumeric Symbols block, so a caption can appear bold even when a platform strips fonts, rich text, or markdown. Creators paste those glyphs into bios, story stickers, product titles, and comment replies because the style travels with the characters themselves rather than with a stylesheet. Spaces, punctuation, hashtags, emoji, and other scripts pass through unchanged and are listed in an unmapped report so you always know what did not convert.
How Mathematical Bold maps letters and digits
Unicode Mathematical Bold is a fixed code-point assignment inside the Mathematical Alphanumeric Symbols block, not a font weight applied by a word processor. Capital A maps to U+1D400, capital Z to U+1D419, lowercase a to U+1D41A, lowercase z to U+1D433, digit zero to U+1D7CE, and digit nine to U+1D7D7, with every letter and digit in between following a contiguous offset from those bases.
Encode walks each Unicode scalar value in your string, replaces every plain Latin letter and digit with the matching bold code point, and leaves everything else in place. Decode walks the same way in reverse: each Mathematical Bold letter or digit becomes the corresponding ASCII character, while spaces, punctuation, and unrelated symbols stay as they are. Because surrogate pairs sit outside the Basic Multilingual Plane, the implementation iterates by code point rather than by UTF-16 unit, so a single bold character is never split into half of a pair.
Where Unicode bold text shows up in real work
Social media managers and creators still reach for styled Unicode when a bio, carousel caption, or story sticker must stand out without platform-native formatting controls that vanish on share. E-commerce teams generate product title variants for marketplaces that accept plain text only but render Mathematical Bold glyphs in customer feeds. Growth and community tools need a deterministic encode path so every scheduled post uses the same alphabet rather than a one-off paste from an unreliable generator site.
Support desks receive bold Unicode from customers and need a reliable decode path back to searchable plain text for ticketing and knowledge bases. If you need HTML bold tags, CSS font-weight, other mathematical styles such as italic or fraktur, Braille translation, or leetspeak substitutions, treat those as separate search intents and landings rather than overloading this Mathematical Bold page.
What you can do with it
Social captions and profile bios
Style letters and digits in bios, story stickers, and post captions with copy-paste Mathematical Bold that survives platform plain-text fields.
Decode bold paste into searchable plain text
Convert customer messages or scraped titles that use Mathematical Bold back to ordinary ASCII for search, CRM, and knowledge-base indexing.
FAQ
What characters can become Mathematical Bold?
Latin letters A–Z and a–z plus digits 0–9. Spaces, punctuation, emoji, and other scripts pass through unchanged and are listed in the unmapped field.
How does auto mode choose direction?
If the input contains any Mathematical Bold letter or digit, auto decodes to plain text. Otherwise it encodes plain letters and digits to bold.
Is this the same as CSS or HTML bold?
No. This emits Unicode Mathematical Bold code points that travel inside the text itself. HTML tags and CSS font-weight are separate mechanisms that platforms often strip.
What happens to characters that cannot map?
They stay in the result in their original form.
What does it cost?
The browser tool is free and runs locally.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/enc/mathematical-bold \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"text":"Hello World 2026"}'const res = await fetch("https://api.kit.forhosting.com/enc/mathematical-bold", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"text": "Hello World 2026"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/enc/mathematical-bold",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"text": "Hello World 2026"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/enc/mathematical-bold", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"text":"Hello World 2026"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"text":"Hello World 2026"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/enc/mathematical-bold", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"text": "Hello World 2026"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "enc.mathematical_bold",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
This capability maps A through Z, a through z, and digits zero through nine in either direction: encode produces Mathematical Bold code points, decode restores plain ASCII, and auto mode picks the direction by detecting whether any bold letter or digit is already present.
How Mathematical Bold maps letters and digits
Characters that have no bold counterpart—commas, spaces, emoji, CJK ideographs, currency signs—are not invented or dropped; they pass through and appear once each in the unmapped list so API clients can audit coverage. This page implements only the Mathematical Bold alphabet and digits, not italic, bold italic, fraktur, double-struck, monospace, or sans-serif mathematical styles, which are separate code ranges and separate search intents.
What you send and what you get back
Send a required string field named text containing the caption, title, or label you want to style or restore. Optionally send mode as encode, decode, or auto; when omitted, auto is the default. Classic checks include encoding Hello World 2026 into bold letters and digits while listing space as unmapped, decoding a bold phrase back to plain ASCII, and confirming that an empty text field is rejected rather than returned unchanged. Aliases such as input, value, data, message, and string are accepted for the same field so scripts can reuse existing payload shapes. Direction aliases such as op, operation, and direction, and short values like enc, dec, to_bold, and from_bold are also accepted. On success the response echoes the original text, returns result as the transformed string, mode as the requested operation, direction as the resolved encode or decode path, mapped as the count of characters that hit the table, unmapped_count and unmapped as the unique passthrough characters that did not map, length as the Unicode scalar length of the result, plus script, block, and standard labels naming Mathematical Bold. Missing text, non-string objects for text, empty strings, unknown mode values, and strings longer than the documented maximum fail with invalid_input and a clear English message. Validation failures do not consume prepaid balance. Pricing for successful API calls is the published base of $0.002 per item.
Where Unicode bold text shows up in real work
Because this capability is a pure parse engine, API pricing is the published base of $0.002 per successful item and failed validation does not consume balance.
Integration use cases
Deterministic fixtures for content pipelines
Generate golden encode and decode vectors so scheduled-post tools and CI checks always apply the same Unicode bold alphabet.