Text & Writing Tools
Base64 Converter — Encode/Decode Text, Images & Audio
Encode or decode Base64 for text, images, and audio files up to 2MB free. Preview images and audio directly from Base64 or a Data URL. No signup.
TL;DR: Encode text to Base64 or decode it back on the Text tab, or upload an image/audio file (up to 2MB each) to get its Base64/Data URL with a live preview — everything processed locally in your browser via FileReader and btoa/atob.
Reviewed by FYN Tools Editorial · Guides ·
Privacy & processing: Encoding and decoding run entirely in your browser using the native btoa/atob functions and FileReader API. Files are never uploaded to a server, and uploads are capped at 2MB.
Base64 Converter
Encode or decode Base64 for text, images, and audio files up to 2MB free. Preview images and audio directly from Base64 or a Data URL. No signup.
- Inputs
- Plain text for the Text tab; an image or audio file up to 2MB for the Image/Audio tabs; or a raw Base64 string / full Data URL for decoding
- Outputs
- Base64-encoded text, a Data URL with live image or audio preview, or decoded plain text
- Processing
- Client-side (browser)
- Limits
- File uploads are capped at 2MB; the Text tab’s btoa/atob only handles Latin1-range characters and will error on emoji or many non-Latin scripts unless pre-encoded
Quick steps
- Choose a tab: Text, Image, or Audio, depending on what you want to convert.
- On the Text tab, choose Encode or Decode, paste your content, and click the action button.
- On the Image or Audio tab, click Choose Image/Audio to upload a file up to 2MB, or switch to decode mode and paste a Base64 string or full Data URL.
- Review the live preview (for image/audio) or the text output (for text mode).
- Click the copy button to copy the Base64 output for use elsewhere.
- Encode text and files to Base64 format
- Decode Base64 strings back to original format
- Support for images, documents, and binary files
- Real-time encoding and decoding
- Copy results to clipboard
- Download decoded files directly
Data input / output
| Inputs | Plain text for the Text tab; an image or audio file up to 2MB for the Image/Audio tabs; or a raw Base64 string / full Data URL for decoding |
|---|---|
| Outputs | Base64-encoded text, a Data URL with live image or audio preview, or decoded plain text |
| Formats | Text tab uses standard Base64 via btoa/atob; Image and Audio tabs produce/accept full data:mime;base64,... URLs |
| Limits | File uploads are capped at 2MB; the Text tab’s btoa/atob only handles Latin1-range characters and will error on emoji or many non-Latin scripts unless pre-encoded |
| Processing | Client-side (browser) |
How to Use the Base64 Converter
- Choose a tab: Text, Image, or Audio, depending on what you want to convert.
- On the Text tab, choose Encode or Decode, paste your content, and click the action button.
- On the Image or Audio tab, click Choose Image/Audio to upload a file up to 2MB, or switch to decode mode and paste a Base64 string or full Data URL.
- Review the live preview (for image/audio) or the text output (for text mode).
- Click the copy button to copy the Base64 output for use elsewhere.
What is a Base64 Converter?
This converter has three tabs for three input types. The Text tab uses the browser’s native btoa/atob functions to encode plain text to Base64 or decode Base64 back to text — note that these functions work on Latin1-range characters, so pasting emoji or many non-Latin scripts without pre-encoding will throw an encoding error rather than silently succeed. The Image and Audio tabs accept file uploads up to 2MB, read them via the FileReader API, and produce both a live preview and the underlying Base64 string.
Decoding on the Image and Audio tabs is flexible: paste a full Data URL (like data:image/png;base64,...) and it previews directly, or paste a raw Base64 string and the tool assumes a reasonable default MIME type (image/png or audio/mpeg) to build a previewable Data URL, with a note that other specific formats need the full Data URL prefix to preview correctly.
Base64 encodes binary or text data into an ASCII-safe string using a 64-character alphabet, commonly used to embed small files directly inside text formats like JSON, CSS, or HTML (as a Data URL) without needing a separate file request. Decoding reverses that process back to the original bytes. This tool keeps the whole round trip client-side: your file or text data is read locally and never uploaded anywhere.
How it works
Base64 Converter reads your input from the panel above, applies encode text and files to base64 format, and shows a result you can copy or download. Options stay visible so you can iterate without reloading the page.
Encode URLs for safe use with our URL Encode Decoder.
Common Use Cases & Examples
- Embedding a small icon in CSS: Upload a small image, copy the resulting Data URL, and paste it directly into a CSS background-image property to avoid an extra HTTP request.
- Debugging an API payload: Decode a Base64 field from an API response to inspect its actual text or binary contents without writing a script.
- Verifying an unknown Data URL: Paste a Base64 string or Data URL from an unfamiliar source into the decode mode to preview it safely before using it elsewhere.
Input / Output Examples
Input
Hello
Output
SGVsbG8=
Frequently Asked Questions
What is Base64 encoding?+
Base64 is a encoding scheme that converts binary data into ASCII text format using 64 printable characters. It's commonly used for transmitting data over text-based protocols.
When should I use Base64 encoding?+
Use Base64 for embedding images in HTML/CSS, sending binary data via email, storing binary data in JSON/XML, or transmitting files through text-only channels.
Can I encode any type of file?+
Yes, you can encode any file type including images, documents, videos, and executables. However, Base64 increases file size by approximately 33%.
Is Base64 encryption or security?+
No, Base64 is encoding, not encryption. It's easily reversible and provides no security. Use proper encryption methods for securing sensitive data.
Key Features
- Encode text and files to Base64 format
- Decode Base64 strings back to original format
- Support for images, documents, and binary files
- Real-time encoding and decoding
- Copy results to clipboard
- Download decoded files directly
Benefits
Embed small assets directly into CSS or HTML without extra file requests.
Debug Base64-encoded API fields without writing a decode script.
Safely preview an unfamiliar Base64 string or Data URL before using it.
When to Use Base64 Converter
- Embedding a small icon or image directly into CSS or HTML as a Data URL
- Encoding text data for safe inclusion in a URL, JSON field, or config value
- Previewing what an unfamiliar Base64 string or Data URL actually renders as
- Quickly decoding a Base64-encoded API response field during debugging
Advantages
- Handles text, image, and audio Base64 conversion in one tool
- Live preview for both image and audio decoding
- Runs entirely client-side — files never leave your browser
- Accepts both raw Base64 strings and full Data URLs for decoding
Tips
- If encoding text with emoji or accented characters throws an error, that is expected — btoa only handles Latin1-range characters directly.
- When decoding a raw Base64 image string without a Data URL prefix, remember the tool assumes a default MIME type (PNG for images, MP3 for audio) unless you provide the full Data URL.
- Keep uploads under 2MB — larger files are rejected before processing to keep the browser responsive.
Common Mistakes
Pasting text with emoji or non-Latin characters into the Text tab’s encode mode and being surprised by an encoding error.
Uploading a file just over the 2MB limit and not realizing why the upload was rejected.
Pasting a raw Base64 audio string and expecting it to preview correctly as an image, or vice versa, without matching the correct tab.
Summary
Use the tabs above to encode or decode text, images, or audio to and from Base64 — everything from file reading to conversion happens locally, with a 2MB cap per upload.