Image to Base64 Encoder — Convert Images Online Free
Drag and drop JPG, PNG, WebP, GIF, or SVG images to instantly get Raw Base64, a Data URI, an HTML img tag, or a CSS background-image declaration. Batch mode lets you process multiple images at once with individual copy buttons for each result.
Drop images here or browse to upload
Supports JPG, PNG, WebP, GIF, SVG — multiple files allowed
How to Convert Images to Base64 Online
- Drag and drop one or more images onto the drop zone, or click to browse and select files. JPEG, PNG, WebP, GIF, SVG, BMP, and AVIF are all supported.
- Choose your Output format from the selector: Raw Base64, Data URI, HTML img tag, or CSS background-image.
- Each image appears as a card with a thumbnail, original file size, encoded Base64 size, MIME type, and pixel dimensions.
- Click the individual Copy button on each card to copy that image's output.
- Changing the format selector instantly updates all cards at once.
- Click Clear All to remove all cards and start over.
Key Features
- Four output formats: Raw Base64, Data URI, HTML img tag, CSS background-image
- Batch mode — convert multiple images simultaneously from one drop or file selection
- Per-image thumbnail, file size, Base64 size, MIME type, and dimension display
- Size warning when encoded output exceeds 100 KB (not recommended for production HTML)
- Format selector updates all cards instantly without re-encoding
- Individual Copy button for each image card
- 100% browser-based using FileReader API — images never leave your device
Image to Base64 Use Cases
Embedding small icons in HTML email templates
HTML email clients often block external image requests for privacy. Embedding icons, logos, and decorative images as Base64 Data URIs ensures they load in every email client, including those with strict security policies, without requiring an image hosting server.
Generating CSS background-image Data URIs
Small decorative patterns, gradients saved as PNG, and custom bullet icons can be embedded directly in a CSS stylesheet as background-image Data URIs. This eliminates the extra HTTP request for the image file, reducing render-blocking resource loads.
Preparing images for JSON API payloads
Some APIs accept image uploads as Base64-encoded strings in JSON request bodies. Select Raw Base64 format and paste the output directly into your JSON payload field without any additional encoding steps.
Creating self-contained HTML documents
Single-file HTML reports, documentation, or interactive demos can embed all images as Data URIs, producing a file that works identically on any device without any internet connection or file dependencies.
FAQ's
Any image format your browser can read is supported — JPEG, PNG, WebP, GIF, SVG, BMP, AVIF, and ICO. The MIME type is automatically detected from the file and included in the Data URI prefix and HTML output.
Base64 encodes every 3 bytes of binary data as 4 ASCII characters, resulting in a ~33% size increase. A 100 KB PNG produces approximately 133 KB of Base64 text. This overhead means Base64 is best suited for small images under 5 KB.
Hold Ctrl (or Cmd on Mac) to select multiple files in the browser dialog, or drag multiple image files onto the drop zone simultaneously. Each image gets its own card with individual output and Copy button.
After loading the file via FileReader, the tool creates a temporary Image object and reads its naturalWidth and naturalHeight properties in pixels. This is displayed in the file info row on each image card.
No. All processing uses the browser's FileReader API entirely client-side. Your images never leave your device. The tool works fully offline once the page has loaded, making it safe for confidential or proprietary images.
When any encoded image exceeds approximately 100 KB in Base64 size, a warning appears. Large Base64 strings increase HTML document size, cannot be cached separately by the browser, and delay page parse time. For large images, serve them as standalone files instead.
Select CSS background-image to get a ready-to-paste background-image: url("data:image/...;base64,...") declaration. You can paste this directly into a CSS rule in your stylesheet or as an inline style attribute.