Free Base64 image encoder and decoder. Convert images to Base64 strings and Base64 back to images.
How to Use the Base64 Image Encoder
Upload an image to get its Base64 string, or paste a Base64 string to decode it back to an image.
About This Tool
Base64 is a binary-to-text encoding scheme that represents binary data (like images) as a string of printable ASCII characters. It works by splitting binary data into 6-bit groups and mapping each group to one of 64 characters (A–Z, a–z, 0–9, +, /). The resulting string is about 33% larger than the original binary, but it can be safely embedded directly in HTML, CSS, JSON, and XML where raw binary data would break the parser. Common uses include embedding small icons in CSS as data URIs (avoiding extra HTTP requests), sending images in JSON API payloads, and storing thumbnails in databases as text. This tool encodes images to Base64 and decodes Base64 strings back to viewable images, entirely in your browser.
Frequently Asked Questions
Are my images uploaded to a server?
No. All encoding and decoding happens locally in your browser. Your images and Base64 strings never leave your device.
What file formats are supported?
The encoder accepts any image your browser can display, including PNG, JPG, WebP, GIF, BMP, and SVG. The decoder accepts any valid Base64 image string or data URI.
Is there a file size limit?
No hard limit, but keep in mind that Base64 encoding increases file size by approximately 33%. Very large images may produce long strings.
Why is the Base64 string larger than the original file?
Base64 represents 6 bits of data per character, while raw binary stores 8 bits per byte. This means 3 bytes of binary become 4 Base64 characters, resulting in a 33% size increase. This overhead is the trade-off for being able to embed binary data in text formats.
When should I use Base64 instead of a separate image file?
Use Base64 for small images (under 10 KB) like icons, logos, and UI elements where eliminating an HTTP request improves performance. For larger images, a separate file is more efficient because browsers can cache it independently and the 33% size overhead becomes significant.