Why does the encoded output sometimes end with = signs?

Padding. Base64 outputs in multiples of 4 characters — if the input length isn't a multiple of 3 bytes, the last 4-character group is padded with = to fill it out. The URL-safe variant typically drops the padding.

Why does my Urdu/emoji text get encoded weirdly?

It shouldn't — this converter uses TextEncoder which produces UTF-8 bytes first, so non-ASCII characters round-trip correctly. If you're seeing garbage, check that the decoder also handles UTF-8 (some legacy decoders assume Latin-1).

What's the size overhead?

About 33%. 3 bytes of input become 4 base64 characters. So a 1 MB file becomes ~1.37 MB encoded. Worth it for transport-safety; avoid for large files where you can use multipart upload instead.

What's the difference between Base64 and Base64URL?

Base64URL replaces + with - and / with _ (so it's safe in URLs without further escaping) and typically drops the = padding. Used in JWT, OAuth, and many web APIs.

Base64 Encode / Decode

Utility

Encode text or files to Base64 (and back). UTF-8 safe + URL-safe variant supported.

Utility

Base64 Encode / Decode

Generated on April 25, 2026

Plain textBase64URL-safe (-_ no padding) Encode file

Input (Plain text)

Output (Base64)

?What is the Base64 Encode / Decode?

Base64 encodes binary data using only 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). It's the standard way to embed binary content (images, files, encryption keys) in text-only contexts: email attachments (MIME), JSON payloads, data: URLs, JWT tokens, and Basic-Auth headers. This converter is fully UTF-8 safe — non-ASCII text like Urdu, Arabic, or emoji round-trips correctly. The optional URL-safe variant (RFC 4648 §5) replaces + with - and / with _ and drops padding, which is required for URL parameters and JWT segments.

The Formula

Base64: 3 binary bytes (24 bits) → 4 characters (6 bits each). Output size ≈ 4/3 × input size, rounded up to a multiple of 4 (with = padding).

Practical Examples

Embed a small image directly in HTML/CSS as a data: URL: `data:image/png;base64,iVBORw0KG…`.

JWT (JSON Web Token) segments are Base64URL-encoded — the URL-safe variant is critical here.

HTTP Basic-Auth: `Authorization: Basic ` + base64(username:password).

MIME email attachments use Base64 to fit binary files into 7-bit-clean SMTP transport.

Embedding small SVGs in CSS background-image properties.

Frequently Asked Questions

No — it's just an encoding. Anyone can decode it instantly. Don't use it to 'hide' sensitive data; use real encryption (AES, libsodium) for that.

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Base64 Encode / Decode

Base64 Encode / Decode

?What is the Base64 Encode / Decode?

The Formula

Practical Examples

Frequently Asked Questions

Is Base64 encryption?

Why does the encoded output sometimes end with = signs?

Why does my Urdu/emoji text get encoded weirdly?

What's the size overhead?

What's the difference between Base64 and Base64URL?

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