Base64 MIME Encoding With 76-Character Lines
MIME Base64 wraps lines at 76 characters. See what wrapped output looks like for email attachments and PEM-style data.
Part of the free Base64 Encoder. Runs in your browser — nothing is uploaded.
Base64 MIME Encoding With 76-Character Lines
Email standards (MIME) require Base64 lines of at most 76 characters. Many tools output one long line instead, which some systems reject. This example shows what wrapped output looks like for a longer input.
Worked example: A longer text, wrapped at 76 characters
Text
Base64 turns binary or text into a safe ASCII alphabet so it can travel through systems that only handle plain text, such as email bodies, JSON fields and URLs.
MIME Base64
QmFzZTY0IHR1cm5zIGJpbmFyeSBvciB0ZXh0IGludG8gYSBzYWZlIEFTQ0lJIGFscGhhYmV0IHNv IGl0IGNhbiB0cmF2ZWwgdGhyb3VnaCBzeXN0ZW1zIHRoYXQgb25seSBoYW5kbGUgcGxhaW4gdGV4 dCwgc3VjaCBhcyBlbWFpbCBib2RpZXMsIEpTT04gZmllbGRzIGFuZCBVUkxzLg==
Practical tip
PEM files (certificates and keys) use 64-character lines instead of 76. Check which width your system expects before wrapping.
How to use this Base64 Encoder
- 1Use the live tool above — it runs entirely in your browser and never uploads your data.
- 2Paste the sample from the worked example, or use your own input.
- 3Copy the result, then adapt the same steps in your editor, script, or pipeline.
Base64 MIME Encoding With 76-Character Lines FAQs
Do decoders accept line breaks?
Most do. Standard decoders ignore whitespace and line breaks, but some strict ones require a single unbroken line.
Why 76 characters?
The limit comes from early email systems with line-length restrictions. MIME (RFC 2045) set 76 as the maximum for encoded lines.
More Base64 Encoder pages
- Encode a String to Base64Encode any text string to Base64 online. Paste your text and copy the result instantly. Supports UTF-8, free and processed in your browser.
- Base64 Encode UTF-8 Text and EmojiEncode Unicode text, accents and emoji to Base64 correctly. Avoid the btoa "Invalid character" error by encoding as UTF-8 first.
- Base64URL Encoder (URL-Safe Base64)Encode text to URL-safe Base64 (Base64URL) with - and _ instead of + and /, and no padding. The format used in JWTs and URLs.
- HTTP Basic Auth Header GeneratorGenerate an HTTP Basic Authorization header by Base64-encoding username:password. Build the header for curl, fetch and Postman.
- Encode JSON to Base64Encode a JSON object to Base64 for headers, query strings and config values. Paste JSON and copy the encoded string. Free and local.
- Base64 Encode in JavaScriptEncode a string to Base64 in JavaScript with btoa() in the browser or Buffer in Node.js. Check your result with the encoder before shipping.
- Base64 Encode a URLBase64 encode a URL to pass it safely as a parameter, hide it from casual reading or store it in a single token. Use Base64URL for safer links.
- Base64 Encode in PythonEncode a string to Base64 in Python with base64.b64encode. Remember to encode to bytes first and decode the result. Verify with the online encoder.
- Base64 Encoding Without PaddingEncode to Base64 without = padding characters. See when padding is optional, how to add it back, and why JWTs omit it.