Base64 Encoder / Decoder
Instantly encode text or files to Base64, or decode Base64 strings back to plain text. Supports standard and URL-safe Base64. Everything runs 100% in your browser — nothing is sent to any server.
What is Base64 Encoding?
Base64 is a binary-to-text encoding scheme that converts arbitrary binary data into a string of 64 printable ASCII characters: A–Z, a–z, 0–9, +, and / (with = used for padding). It was designed to safely transport binary data — like images or files — through systems that only support plain text, such as email (MIME) or JSON APIs.
Every 3 bytes of input are converted into 4 Base64 characters, which means encoded output is always approximately 33% larger than the original input. Decoding reverses this process exactly, recovering the original bytes without any loss.
Common Use Cases
data:image/png;base64,… to eliminate extra HTTP requests.Standard vs URL-Safe Base64
Standard Base64 uses + and / as its 62nd and 63rd characters. These are special characters in URLs, so URL-safe Base64 replaces them with - and _ respectively. The padding character = is also sometimes omitted in URL-safe variants. Use URL-safe when encoding data for JWTs, OAuth tokens, or anything embedded in a URL query string.
Frequently Asked Questions
=) are added to make the output length a multiple of 4. One = means 1 byte of padding; == means 2 bytes of padding.Enjoying this tool?
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