Image to Base64 Converter
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What is Image to Base64 Converter
This tool converts any image file (PNG, JPG, GIF, WebP, SVG) into a Base64-encoded string — the format required to embed images directly in JSON API calls, HTML, CSS, and multimodal AI requests. Base64 encoding converts binary image data into a sequence of ASCII characters that can be safely transmitted as text. This is especially useful when working with multimodal LLMs like GPT-4 Vision, Claude, and Gemini that accept inline images in their API calls.
How to use
- Click the upload area or drag and drop an image file.
- Choose output format: With data URL prefix (data:image/png;base64,...) for use in HTML, CSS, and AI API calls, or Base64 only for raw encoding.
- Click the Copy button to copy the Base64 string to your clipboard.
- Paste the string directly into your API call, HTML img src attribute, or CSS background-image.
When to use it
Need to send an image to the Claude or GPT-4 Vision API without hosting it on a server first? Drag it into the converter, copy the full data URL string (data:image/jpeg;base64,...), and paste it straight into the image_url field of your request. No upload, no hosting, no URL to manage: the image travels inline with the JSON payload.
Frequently asked questions
What image formats are supported?
PNG, JPG/JPEG, GIF, WebP, SVG, and BMP are all supported. Any image format your browser can display can be converted to Base64 here.
What is the difference between data URL and raw Base64?
A data URL includes the MIME type prefix (e.g. data:image/png;base64,) followed by the Base64 string. This format is required for HTML img src attributes, CSS background-image, and most AI API calls. Raw Base64 is just the encoded string without the prefix — useful when the system you're sending to adds its own prefix.
Is there a file size limit?
No server-side limit. The conversion runs in your browser. Very large images (over 10 MB) may slow down the page slightly, but there is no hard limit. Note that most AI vision APIs have their own image size limits — GPT-4 Vision and Claude support images up to 20 MB.
Is my image uploaded anywhere?
No. The entire conversion happens locally in your browser using the FileReader API. Your image never leaves your device.
Why does the Base64 string look so long?
Base64 encoding expands binary data by approximately 33%. A 100 KB image becomes roughly 133 KB as a Base64 string. This is expected and the string is lossless — decoding it produces the exact original image.
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