Encode and decode Base64 text
Convert text to Base64 or decode it back, with full Unicode support and an optional URL-safe alphabet for links and filenames.
How it works
Choose a direction
Encode text to Base64, or decode it back.
Paste your content
Unicode and emoji are handled correctly.
Pick an alphabet
The URL-safe variant replaces plus and slash.
It is processed on your machine
This is the kind of content people are most nervous about pasting into a website. Here nothing is transmitted: your browser reads the input, the tool works on it in the tab, and the result is handed straight back. Close the tab and it is gone.
- Opened from your disk by your browser — not sent anywhere first.
- Held in the tab while the tool works, then dropped.
- Saved to your device by your browser, not by a link to a server.
- Closing the tab clears the working copy completely.
- No account, so nothing is ever attached to an identity.
- No tracking of what you worked on or what was inside the file.
There is no queue and no retention policy to read. Whatever you pasted is released the moment the tab closes. See how your data stays inside the tab for the full picture, or follow the DevTools check to verify your file never leaves.
What people use it for
Moving binary data through a text channel
Email bodies, JSON fields and URLs only accept text. Base64 makes binary safe to travel through them.
Checking something before you ship it
A quick pass in the browser is faster than wiring up a build step for a one-off job.
Working on a machine you do not control
Because nothing is transmitted, it is safe to use on a shared or locked-down computer.
Handling data you are not allowed to upload
Customer records, keys and internal names often may not leave the organisation at all. Here they do not.
Formats & limits
What this tool accepts, what it produces, and what it will never ask you for.
- Input
- text or Base64
- Output
- Base64 text, or the decoded original
- Maximum file size
- Set by your device, not by a plan
- Files per run
- Not applicable — nothing is uploaded
- Sign-up required
- None
- Watermark
- Never added
- Works offline
- Yes, once the page has loaded
- Supported browsers
- Any current Chrome, Edge, Firefox or Safari
When something goes wrong
Invalid input stops with a plain message that points at the exact problem, rather than a spinner that never finishes.
The content is not in the shape this tool expects. Check for a missing bracket or an extra character and try again.
Why not an online service
A hosted version of this tool means your input is transmitted to a server you have no relationship with. Removing that step removes the whole category of risk.
A typical upload site
This tool
Questions
What is Base64 actually for?
It represents arbitrary binary data using only printable characters, so it can travel safely through systems that were designed for text, such as email bodies, JSON and URLs.
Does Base64 provide any security?
No. It is an encoding, not encryption, and anyone can reverse it instantly. Never use it to protect a password or a secret.
Why is the output larger than the input?
Base64 represents every three bytes as four characters, so the result is roughly 33 percent larger than the original. That overhead is the cost of making binary data text-safe.
When should I use the URL-safe alphabet?
Standard Base64 uses plus and slash, which have special meanings in URLs and filenames. The URL-safe variant substitutes a hyphen and an underscore so the result can be used safely in a link.
Does it work without an internet connection?
Yes, once the page has loaded. Nothing is fetched while you work, so a dropped connection does not interrupt a run.
Do I need an account or an email address?
No. There is nothing to sign up for, and nothing is ever attached to an identity because no file leaves your device.