Resize image
Upload an image, enter the width or height you need and download the resized file.
Drag your image here or click to choose it
Supports JPG, PNG and WebP
With the ratio locked you only need to fill one side; the other is derived.
Your file never leaves your browser: everything is processed on your device.
How resizing works
The tool works out the target size and repaints the image on a canvas of those dimensions using the browser's smoothed resampling. The result is then encoded again in the format you pick.
height = width × (original height ÷ original width)
With the ratio locked, the side you leave empty is derived from the original: height = width ÷ (original width ÷ original height). If you fill both sides with the ratio locked, the image is fitted to the largest size that fits inside that box.
scale = final width ÷ original width
Scaling down always works well. Scaling above the original size cannot invent detail: the browser interpolates pixels and the image looks softer.
Worked example
A 4000 × 3000 px photo where you only enter 1200 px of width with the ratio locked becomes 1200 × 900 px, a 30% scale.
Frequently asked questions
- Will the image be distorted if I set both sides?
- Only if you untick the keep aspect ratio box. With the ratio on, the image is fitted inside the box you asked for without stretching.
- Can I enlarge a small image?
- You can, but detail that was never captured cannot come back: the result will look blurrier. For big enlargements, start from a higher resolution original.
- How is this different from changing the resolution?
- Here you change the real pixels. Changing the resolution (DPI) affects the size at which the image prints, not how many pixels it holds.
- Can I change format while resizing?
- Yes, pick the output format in the selector: you can resize and move to JPG, PNG or WebP in a single step.