Do you upload my data to a server?

No. Everything happens in your browser. Your base64 string is never transmitted anywhere.

What image formats are supported?

Any format your browser can show, including PNG, JPEG, GIF, WebP, BMP, AVIF, ICO and SVG. The tool reads the format from the first bytes of the data, so the label and the download extension are right without a prefix, or when the prefix names the wrong type. Data that is not an image, such as plain text, gets an error that says so.

Should I include the "data:image/..." prefix?

Either works. With or without the data:image/...;base64, prefix, the tool finds the format from the image bytes. A data URI can also be split over several lines, as email and some APIs do every 76 characters, and SVG can be pasted as plain markup.

My string is very long — will the tool handle it?

Yes, up to your browser's limit for data URLs. MDN lists 512 MB for Chrome and for Firefox 136 or later (older Firefox stops at 32 MB) and 2 GB for Safari. Decoding runs in your browser, so a string of tens of megabytes can take a few seconds and a lot of memory.

Why does my image appear broken?

The string may be cut off, may not be an image, or may be damaged. The tool already removes spaces, line breaks and surrounding quotes, accepts URL-safe base64 with - and _, and adds missing = padding. If it still fails, the error names the problem, such as the first character that is not base64 or a length that shows the string was cut off.

How do I convert base64 to an image in JavaScript or Python?

In a web page, set an img src to data:image/png;base64, followed by the string. In Node.js, run fs.writeFileSync('out.png', Buffer.from(b64, 'base64')). In Python, run open('out.png', 'wb').write(base64.b64decode(b64)). Remove any data: prefix before decoding in Node.js or Python.

How big will the image file be?

About three quarters of the string length, because base64 stores 3 bytes in every 4 characters and adds about 33% to the file. Subtract one byte for each = at the end. A 40,000-character string is about 29.3 KB and a 1,000,000-character string about 732.4 KB. The tool shows this as Size after you decode.

Base64 To Image

Paste a base64 string to instantly preview and download the decoded image in your browser.

Paste the base64 string, with or without the data:image/...;base64, prefix, and click Decode to preview the image, see its format, size and dimensions, and download it.

Base64 Input

Paste a base64 string on the left and click Decode

Done!

Quick answer

Paste the base64 string, with or without the data:image/...;base64, prefix, and click Decode to preview the image, see its format, size and dimensions, and download it. Line breaks, spaces, quotes, URL-safe - and _ and missing = padding are accepted, and raw SVG markup works too. The format comes from the first bytes: iVBORw0KGgo is PNG, /9j/ is JPEG and R0lGOD is GIF. Every 4 base64 characters hold 3 bytes, so a 40,000-character string is a file of about 29.3 KB.

Examples

String starts with	Format
iVBORw0KGgo	PNG
/9j/	JPEG
R0lGOD	GIF
UklGR	WebP (RIFF)
Qk	BMP
PHN2Zy or PD94bWwg	SVG

Paste your base64 string and click Decode.

Summary

This tool decodes a base64-encoded string directly in your browser and renders the resulting image for immediate preview. No files are uploaded to any server — the entire conversion runs client-side using the native HTML5 Image API. Supports PNG, JPEG, GIF, WebP, and SVG data URIs.

How it works

Paste your base64 string (with or without the data URI prefix) into the input area.
The tool detects the format from the first bytes of the decoded data.
The decoded image is rendered instantly in the preview panel.
Review the image dimensions and file size displayed below the preview.
Click Download to save the image to your device.

Use cases

Preview base64-encoded images embedded in JSON API responses.
Inspect inline images stored in a database or configuration file.
Verify that an image was correctly encoded to base64 before sending it.
Extract and save embedded images from email or HTML source code.
Debug broken <img src="data:..."> tags by pasting the base64 payload.
Convert a base64 string from a backend response into a downloadable file.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu