Contrast Adjuster

Increase or decrease image contrast with a live preview slider. Runs entirely in your browser.

Adjust image contrast

Upload an image, then drag the slider to increase or decrease contrast. The preview updates instantly.

Drag & drop an image here, or click to browse
Supports JPG, PNG and WEBP.

    Preview

    Live preview
    Your image is processed locally in this browser tab using the Canvas API. It is never uploaded to Calcooo or any server.

    How to use this tool

    1. Drag and drop an image into the box above, or click to browse and select one.
    2. Drag the Contrast slider left to flatten, or right to increase contrast. The preview updates live.
    3. Use Reset to return to the original contrast at any time.
    4. Click Download image to save the result.

    FAQ

    Frequently asked questions

    Is my image uploaded anywhere when I adjust contrast?

    No. The image is processed locally in your browser using the Canvas API. It never leaves your device.

    What does 100% contrast mean?

    100% is the original, unchanged contrast of your image. Moving the slider below 100% flattens the contrast, and moving it above 100% makes darks darker and lights lighter.

    Does this change the file format?

    No. The downloaded image is exported in the same format as the original file you uploaded.

    Can I combine this with other adjustments?

    This tool only adjusts contrast. If you also want to change brightness, saturation or convert to grayscale, see the other Image Editing tools, or use Image Filters to adjust all of them together on one page.