Enter text or Base64 above to get started
Try an example, or enter your own text above.
How to use the Base64 Encoder/Decoder
- Type or paste the text or Base64 string you want to convert.
- Tap Encode to convert plain text to Base64, or Decode to convert Base64 back to text.
- The converted output appears instantly below.
- Use the Copy or Share buttons to save or send your result.
Tip: Base64 is not encryption — it just represents binary or text data using a safe 64-character alphabet, so anyone can decode it back to the original. Don't use it to hide sensitive information.
Common mistakes to avoid
- Assuming Base64 encoding provides security or privacy — it doesn't, it's just a text-safe encoding.
- Trying to decode a string that isn't valid Base64 (wrong length, invalid characters) and expecting readable output.
- Forgetting that encoded output is roughly 33% longer than the original text.
How the Base64 Encoder/Decoder Works
Text to Base64 and back
Base64 encoding takes any text (or binary data) and represents it using only 64 safe characters (A-Z, a-z, 0-9, + and /), which is why it's commonly used to embed data inside URLs, JSON, email attachments, and data URIs like the one this very page uses for its logo. This tool uses the browser's own atob() and btoa() functions, wrapped with UTF-8 handling so accented letters, emoji, and non-Latin scripts encode and decode correctly.
When to use this tool
Use it when you need to embed small files or images as data URIs, decode a Base64 payload from an API response or JWT token, or prepare text for systems that don't support raw binary or special characters.
✓ Pros
- Works instantly, right in your browser
- Correctly handles Unicode text, not just plain ASCII
- No sign-up, no ads blocking the result
✕ Limitations
- Base64 is an encoding, not encryption — anyone can decode it back to the original, so never use it to protect secrets.
- Encoded text is about 33% larger than the original, which matters for very large inputs.
- It doesn't decode Base64 that's been altered, truncated, or mixed with other encodings.
Where Base64 Is Used
Common real-world use cases
Base64 shows up in more places than most developers realize. Here are the situations where you're most likely to run into it.
Common use cases
- Data URIs: embedding small images or fonts directly inside HTML/CSS without a separate file request.
- Email attachments: MIME email encodes binary attachments as Base64 text.
- JWT tokens: the header and payload segments of a JSON Web Token are Base64-URL encoded.
- Basic Auth headers: HTTP Basic Authentication sends "username:password" as a Base64 string.
Why Text Looks Longer After Encoding
Base64 converts data 3 bytes at a time into 4 output characters, which is why encoded text is roughly 33% larger than the original — for example, the 5-character text "Hello" (5 bytes) becomes the 8-character string "SGVsbG8=", and longer inputs follow the same ratio. The "=" padding at the end simply fills out the final group to a multiple of 4 characters when the input length isn't evenly divisible by 3.
Quick Reference: Text to Base64
A few short examples showing exactly how plain text converts to Base64:
| Plain text | Base64 encoded | Note |
|---|---|---|
Hello | SGVsbG8= | 5 bytes → 8 characters |
Hello, World! | SGVsbG8sIFdvcmxkIQ== | 13 bytes → 20 characters |
TickmarkTools | VGlja21hcmtUb29scw== | 13 bytes → 20 characters |
A | QQ== | 1 byte → 4 characters (padded) |
Base64 output length is always a multiple of 4 characters, padded with "=" where needed.
Features
Full Unicode support
Instant encode/decode
No data stored
Mobile friendly
How TickmarkTools compares
An honest, feature-by-feature look at browser-based developer tools.
| Feature | TickmarkTools | Typical free sites | Premium suites |
|---|---|---|---|
| Price | Free | Free / freemium | Free tier + paid plans |
| Sign-up required | No | Often yes | Yes |
| Data leaves your device | Never | Usually | Usually |
| Watermark on export | None | Sometimes | On free tier |
| Mobile friendly | ✓ | Varies | ✓ |
| Works without account | ✓ | Varies | ✗ |
These are general, illustrative observations about common patterns across free online calculator tools as a category — not verified or benchmarked data about any specific named competitor or product. Individual sites vary and may differ from what's shown here.
Why you can trust this tool
No data stored
Your input is never saved or logged.
Secure processing
All processing happens client-side in your browser.
Fast processing
Results render in milliseconds, no waiting.
Mobile friendly
Use this tool from any device.
No sign-up
No account, no email, no watermark.
Works offline*
Once loaded, this tool needs no internet connection.
Accuracy & limitations
This tool encodes and decodes accurately, but it's worth understanding what Base64 is and isn't:
- Not encryption. Base64 is a reversible text encoding, not a security mechanism — anyone can decode it instantly, so don't use it to protect passwords or secrets.
- Larger output. Encoded text is about 33% bigger than the input, which can matter for very large payloads.
- Strict decoding. Decoding will fail on strings that aren't valid Base64, such as text with invalid characters or incorrect padding.
Base64 Encoder/Decoder FAQ
Yes, the Base64 Encoder/Decoder is completely free with no sign-up required.
No. Base64 is a reversible text encoding, not encryption — it provides no security or privacy, since anyone can decode it instantly.
Base64 converts data 3 bytes at a time into 4 output characters, which makes encoded text roughly 33% larger than the original.
Yes. It handles full Unicode text correctly, not just plain ASCII, so emoji and accented letters encode and decode cleanly.
The string you pasted likely isn't valid Base64 — check for missing padding, extra spaces, or characters outside the standard Base64 alphabet.
No. All calculations run entirely in your browser, and nothing you enter is ever sent to a server or stored.
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