Base64 converter
Encode text or files such as images to Base64, or decode Base64 back to the original text or file.
Text or file
0 characters · 0 lines
Direction
0 characters · 0 lines
Everything runs on this device. What you enter is never sent anywhere.
Base64 isn't encryption. Anyone can decode it, so don't use it to hide passwords or other secrets.
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How to use
1. Enter text
Tap “Paste” to put in the text you copied. You can also type straight into the box. The Base64 appears below right away. To encode an image or other file, open it with “File”.
Click “Paste” above the left box to put in the text you copied. You can also type straight into the box. The Base64 appears on the right right away. To encode an image or other file, use “Open file” or drag it onto the page.
2. Choose a format
In the bar above the result, tap “URL-safe” to turn + / into - _ and drop the trailing =. Tap “data URL” to add a type starting with data: at the beginning. The result below changes instantly.
In the bar above the right box, click “URL-safe” to turn + / into - _ and drop the trailing =. Click “data URL” to add a type starting with data: at the beginning. The result below changes instantly.
3. Copy or save
Tap “Copy” below the result to copy the Base64. Tap “Download text” to save it as a .txt file. For an image turned into a data URL, “Copy as HTML” and “Copy as CSS” copy it ready to use as an img tag or a background-image.
Click “Copy” below the right box to copy the Base64. Click “Download text” to save it as a .txt file. For an image turned into a data URL, “Copy as HTML” and “Copy as CSS” copy it ready to use as an img tag or a background-image.
4. Decode Base64
Tap “Decode” in the bar, then tap “Paste” above the box to put in the Base64. Text appears below as is. An image is shown below, and you can tap “Download file” to save it as an image file. Paste an email subject or sender like “=?UTF-8?B?…?=” and it turns back into the original text too.
Click “Decode” in the bar on the right, then click “Paste” above the left box to put in the Base64. Text appears on the right as is. An image is shown on the right, and you can click “Download file” to save it as an image file. Paste an email subject or sender like “=?UTF-8?B?…?=” and it turns back into the original text too.
Great for
Reading an email subject or API response
Paste a subject or sender that shows up as “=?ISO-2022-JP?B?…?=” in an email's source, or Base64 from an API response, and it turns back into readable text, including non-English characters. Legacy encodings such as Shift_JIS and the Q form (=E3=81=82) work too.
Web developers and support staff
Embedding images in HTML or CSS
Open a small image such as an icon and click “data URL”. “Copy as HTML” copies it as <img src="…">, and “Copy as CSS” as background-image: url("…").
Web designers and front-end developers
Putting data in a URL or JSON
Turn on “URL-safe” to get the same - _ form used in URL parameters and JWTs, so nothing breaks when you paste it.
Anyone testing APIs
Turning Base64 back into a file
Paste a Base64 image or PDF from a log or config, and it identifies the type and saves it as a file with the right extension.
Developers and people who work with data
Good to know
- Base64 isn't encryption. Anyone can decode it, so don't use it to hide passwords or other secrets.
- Base64 makes data about 1.33 times larger. Turning a large image into a data URL makes your HTML heavier.
- Files up to 30 MB can be encoded. Larger files can make some devices slow.
About Base64
Base64 is a way to write data such as images using only 64 characters: letters, digits, “+” and “/”. Every 3 bytes become 4 characters, so the size grows by about 1.33 times. It's used to carry data through places that only accept text, such as email attachments, data URLs, JWTs and API authentication (Basic auth).
This tool always converts text to UTF-8 first, so non-English text and emoji never get garbled. When decoding, it reads the input as is, even with line breaks or spaces, URL-safe - _, a missing trailing =, or a data URL prefix. Text is shown as text, images are displayed, and other files are identified by type so you can save them.
FAQ
Answers to common questions before you start.
Is my text or file sent anywhere?
No. Encoding and decoding happen entirely in your device's browser, and nothing you enter is sent to a server.
Will non-English text get garbled?
No. Text is converted to UTF-8 first, so non-English text and emoji come back exactly as they were. When decoding, if it can't be read as UTF-8, it checks whether it was written in a legacy Japanese encoding such as Shift_JIS or EUC-JP.
How do I convert an image to Base64?
With “Encode” selected, click “Open file” and pick an image, or drag an image onto the page. The Base64 appears right away. To use it in HTML or CSS, turn on “data URL”.
Can I turn Base64 back into an image or file?
Yes. Switch to “Decode” and paste the Base64. If it's an image, it's displayed, and you can save it with “Download file”. PNG, JPEG, PDF, ZIP and more are identified from their content and given the right extension.
My email subject looks like “=?UTF-8?B?…?=”
That's the form used to send email subjects and senders using only letters and numbers (MIME encoding). Switch to “Decode” and paste the line: it turns back into the original text, and the character set it read (UTF-8, ISO-2022-JP and so on) appears above the result. Several in a row and folded lines are read together.
What is URL-safe?
It's a form that replaces “+” and “/”, which have special meanings in URLs and file names, with “-” and “_”, and drops the trailing “=” (base64url). It's used in JWTs and URL parameters. When decoding, either form is read automatically.
What is a data URL?
It's Base64 with the data type added at the start, like “data:image/png;base64,”. Put it in an HTML img src or a CSS url() to show the image without loading a separate file. For images, “Copy as HTML” and “Copy as CSS” copy it in a ready-to-paste form.
It says “This can't be read as Base64”
Either there's a character Base64 can't use, or part of it was cut off when you copied it. The line and column are shown, and the spot is marked in orange in the input box, so check there. Don't worry about line breaks, spaces, or whether there's a trailing =.
Is Base64 encryption?
No. It just swaps data for characters using a fixed table, so anyone can decode it. Don't use it to hide passwords or personal information.
Can it handle large files?
Files up to 30 MB can be encoded. When the result is very long, only the first part is shown in the box, but “Copy” and “Download text” use the whole thing.
Is it free?
Yes, it's free. No sign-up and no ads.
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