Image Resizer Online
Free online image resizer. Change an image to exact pixel dimensions or a scale percent in your browser, lock the aspect ratio, and download as PNG, JPG, or WebP.
Updated 2026-06-14 · Free · No sign-up · Runs privately in your browser
Runs in your browser — no upload. Enter a width/height, or a scale percent (overrides width/height).
What this tool does
This online image resizer changes an image to new pixel dimensions, or a scale percent, and downloads the result, all in your browser. Use it to fit an avatar box, meet a maximum-width rule, shrink a photo for the web, or upscale a small graphic. Nothing is uploaded — the resize runs locally on a canvas.
How to use it
- Click Choose an image and pick your file. The tool fills in its current width and height.
- Type a new Width or Height in pixels. With Lock aspect ratio on, the other field updates automatically.
- Or type a Scale % (for example 50) to resize proportionally — this overrides the width/height boxes.
- Pick an output format: PNG, JPG, or WebP.
- Click Resize & download and check the New dimensions, File size, and Format cards.
How it works
The tool draws your image onto a canvas set to the target width and height, using high-quality smoothing, then exports it in your chosen format. For JPG it fills a white background first because JPEG has no transparency. The aspect-ratio lock simply divides or multiplies by the original width-to-height ratio so proportions stay correct.
Worked example
You have a 4000 x 3000 px photo and need it 800 px wide for a blog.
- Type 800 in Width with Lock aspect ratio on; Height auto-fills to 600.
- Choose JPG and click Resize & download.
- The result is 800 x 600 px, typically a few dozen KB — a big drop from the multi-megabyte original.
Format guide
| Format | Transparency | Best for | Relative size |
|---|---|---|---|
| PNG | Yes | Logos, icons, screenshots, sharp edges | Larger |
| JPG | No (white fill) | Photos | Smaller |
| WebP | Yes | Photos and graphics where supported | Smallest |
Tips
- Resize down, not up, when you can. Enlarging past the original dimensions cannot create detail and looks soft.
- Use a percent for batches of one ratio. A 50% scale halves both dimensions without any maths.
- Keep proportions locked unless you specifically need to distort the image to exact, non-matching dimensions.
Frequently asked questions
How do I resize an image online?+
Choose your image, type the new width or height in pixels (or a scale percent), pick an output format, then click Resize and download. The tool redraws the image at the new size on a canvas and saves it to your device.
Does locking the aspect ratio prevent stretching?+
Yes. With Lock aspect ratio ticked, editing the width auto-fills the matching height (and vice versa) so the image keeps its proportions and never looks squashed or stretched. Untick it to resize to any exact dimensions.
Is my image uploaded to resize it?+
No. Resizing happens entirely in your browser using an HTML canvas, so the image is never uploaded or stored. The tool also works offline once the page has loaded.
Can I make an image larger as well as smaller?+
Yes. Enter dimensions or a percent above 100% to upscale. Note that enlarging cannot add real detail, so a heavily upscaled image will look softer than the original.
Which output format should I choose?+
Use PNG to keep transparency and sharp edges (logos, screenshots), JPG for smaller photo files, and WebP for the smallest files with good quality where the format is supported.