Developers and designers regularly need an image as text: embedding a small logo directly into an HTML email, inlining an icon in CSS, storing a picture in a JSON file, or pasting an image into a config file. That text form is Base64. The NexToolz Image to Base64 Converter encodes any image into both a ready-to-paste data URL and the raw Base64 string, and decodes Base64 back into a viewable, downloadable image.
The encoder shows your file's original size next to the Base64 output size, which matters because Base64 is always larger than the binary file — roughly a third bigger — so it suits small images like icons, logos and signatures rather than full photographs. The data URL output includes the correct MIME prefix (data:image/png;base64,...), so it works immediately in an <img> tag or a CSS background-image.
Everything happens entirely in your browser. Encoding an image normally means uploading it to a stranger's server; here the file never leaves your device, so even a personal photo or an unreleased design is safe to convert. The decoder is equally handy when you receive a block of Base64 — from an API response, a database or an email — and simply want to see what picture it holds.
How to use
Upload an image to encode
Drag & drop or click to browse — the preview, sizes and both outputs appear instantly.
Copy what you need
Copy the full data URL for HTML/CSS, or the raw Base64 string for code and JSON.
Or decode instead
Paste any Base64 string or data URL into the decoder and press "Decode image".
Download the picture
Preview the decoded image and save it as a PNG file.
Frequently asked questions
What is Base64 used for?
Base64 turns binary data like an image into plain text, so it can travel inside text formats: HTML, CSS, JSON, XML and email. Embedding small images as data URLs saves a separate file request and keeps everything in one document.
Why is the Base64 output bigger than my file?
Base64 represents every 3 bytes of the file with 4 text characters, so the encoded text is about 33% larger than the original. That overhead is why Base64 suits icons, logos and small graphics rather than large photos.
What is the difference between the data URL and the Base64 string?
The Base64 string is the encoded image data on its own. A data URL is that same string with a prefix like "data:image/png;base64," in front, which tells the browser what the data is — use the data URL in HTML and CSS, and the plain string in code or JSON.
Why won't my Base64 decode?
The text must be complete and unmodified image data. Truncated strings, line breaks added by email clients, or Base64 of a non-image file will fail. Try copying the string again in full, or paste the complete data URL including its prefix.
Is my image uploaded anywhere?
No. Encoding and decoding both run entirely in your browser. Your files never leave your device, and nothing is stored on any server.
Why use this tool?
Most Base64 converters make you upload your image to their server just to turn it into text. This one reads the file locally, shows the size cost honestly before you embed anything, and works both ways — so a mystery block of Base64 from an API or email becomes a viewable picture again in seconds.
Free forever — no premium tier, no trial and no hidden charges.
Private by design — processing happens in your browser; your files and text are not uploaded.
No signup — open the page and use the tool immediately on phone or computer.