Developer Tools
Base64 Encode and Decode Online
Encode and decode Base64 text or files live — URL-safe, MIME, and data URIs.
Runs locally in your browser — your input is not uploaded.
Need Base32, Hex, Binary, Base58, or Base85? Try the Encoder / Decoder.
What is this tool?
Base64 shows up in data URLs, email attachments, basic-auth headers, and API payloads. Type or paste to convert live, or drop in any file to get its Base64 or a ready-to-paste data URI. Decoding works the other way: readable text appears instantly, and images, PDFs, and other binary data can be previewed or downloaded.
Base64 represents binary data using a safe ASCII alphabet. It is common in data URLs, email attachments, and API payloads.
Encoding expands size by roughly 33%. URL-safe Base64 (Base64URL) replaces + and / with - and _ and is used in JWTs and URLs. MIME email wraps lines at 76 characters.
Your text and files never leave your device — encoding and decoding happen in the browser.
How to use the Base64 Encoder / Decoder
- Choose Encode or Decode.
- To encode, type or paste text, or switch to File and choose any file. The result updates as you type.
- Pick options if you need them: URL-safe alphabet, no padding, 76-character MIME lines, or a data URI prefix for files.
- To decode, paste Base64 (a data URI works too). Text appears right away; binary data such as images can be previewed and downloaded as a file.
- Copy or download the result, or use Swap direction to send it back the other way.
Examples
Encode a greeting
Hello
SGVsbG8=
Frequently asked questions
Can I convert a file or image to Base64?
Yes. Switch to File, choose any file up to 10 MB, and copy the Base64. Turn on Add data URI prefix to get a string you can paste straight into an HTML img tag or CSS.
How do I turn Base64 back into a file?
Choose Decode and paste the Base64. ToolForge detects the file type (PNG, JPEG, PDF, ZIP, and more), previews images, and gives you a download button.
Is Base64 a form of encryption?
No. Base64 is an encoding, not encryption, and anyone can decode it. Never rely on it to hide passwords or secrets.
Does it accept URL-safe Base64?
Yes. When decoding, - and _ are treated as + and /, missing = padding is added, and line breaks and data URI prefixes are ignored. When encoding, tick URL-safe to produce Base64URL.
Why is the encoded text longer than the original?
Base64 uses four characters for every three bytes of input, so the output is about 33% larger.
Want more power later?
Premium tools, higher limits, and API access are on the roadmap. V1 stays free and private in your browser.