Free Resize Image
Resize an image to exact pixel dimensions with a locked aspect ratio or quick 25-200% presets. Save as JPG, PNG, WebP or AVIF locally.
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How to resize an image to exact pixel dimensions
Set a new width or height in pixels, or pick a percentage, and the other side follows the original proportions. Preview the result and its file size before you download.
- Choose an image up to 32 MB. JPG, PNG, WebP, AVIF and other images your browser can open are accepted.
- Type a width or a height in pixels. The other value updates to keep the aspect ratio, or select a scale preset from 25% to 200%.
- Keep the output format, which starts as the format of your image when it is JPEG, PNG, WebP or AVIF, or pick another.
- Adjust quality for JPEG, WebP or AVIF if you also want a smaller file. PNG is saved losslessly.
- Check the output dimensions and size, then select Download image. The file name ends with the new size, such as photo-1080x810.jpg.
When to resize an image
Websites, marketplaces and forms often ask for a specific pixel size. A profile photo may need to be 400 by 400 pixels, a blog may display images at 1200 pixels wide and an online application may set a maximum width for a scanned ID. Phone photos are usually far larger than any of these, so resizing first makes uploads faster and avoids rejected files.
Resizing also saves space. Fewer pixels mean a smaller file at the same quality, which helps email attachments and page speed. If you need a square or a different shape, crop first with the Image Cropper, because resizing here always keeps the original proportions.
Worked example: a 12-megapixel phone photo
Suppose IMG_1234.jpg is 4032 by 3024 pixels. Choose 50% and the output becomes 2016 by 1512 pixels, a quarter of the original pixel count. Type 1080 in the Width field instead and the height becomes 3024 x 1080 / 4032 = 810, so the output is 1080 by 810 pixels and downloads as IMG_1234-1080x810.jpg.
Type 1350 in the Height field and the width becomes 4032 x 1350 / 3024 = 1800, giving 1800 by 1350 pixels. Choosing 200% would ask for 8064 by 6048 pixels, which is 48.8 million pixels. That is above the 40-million limit, so the tool shows an error and you can pick a smaller size.
How resizing works
The image is decoded by your browser and drawn onto a canvas of the new size with high-quality smoothing. The new height is the original height multiplied by the new width divided by the original width, rounded to the nearest whole pixel, so a typed height can shift by one pixel after rounding.
The resized pixels are then encoded locally. For JPEG, PNG and WebP, both the browser encoder and a dedicated encoder run, and the smaller valid file is kept. AVIF uses its dedicated encoder. Metadata such as camera details and location is not copied into the new file. The preview and the size readout show the real encoded result.
Every change you make is applied after a short pause, and any encoding still running for older settings is cancelled. That is why the output panel briefly shows Updating preview before the new size and dimensions appear.
Common mistakes to avoid
Enlarging a small image to meet a minimum size is allowed, but the result can look blurry because no new detail is created. Start from the largest original you have. Another frequent slip is changing the format by accident; check the Output format before downloading, because a PNG photo can be several times larger than a JPEG one.
Finally, remember that resizing keeps the shape of the picture. If a site needs exactly 1080 by 1080 pixels and your photo is 4:3, resizing alone gives 1080 by 810. Crop to a square first, then resize.
Useful tips and limitations
- Shrinking keeps images sharp. Enlarging adds pixels but cannot add detail, so a 200% copy can look soft.
- Each side can be up to 16,384 pixels and the image up to 40 million pixels (16 million for AVIF).
- To hit a file-size limit as well as a size, lower the quality after setting the dimensions and watch the output size.
- Transparent PNG, WebP and AVIF images keep their transparency; JPEG fills it with white.
Common questions
Does Resize Image keep the aspect ratio?
Yes. Width and height are linked, so changing one updates the other from the original proportions. The tool does not stretch or crop.
Can Resize Image make a picture bigger?
Yes. Type a larger width or choose 200%. The image gains pixels, but enlarging cannot recover detail that was not in the original.
What is the largest size Resize Image can create?
Up to 16,384 pixels on a side and 40 million pixels in total, or 16 million pixels when saving as AVIF.
Does Resize Image upload my photo?
No. Decoding, resizing and encoding all run in your browser. The encoder files load from this website.
Why is the height in Resize Image one pixel different from what I typed?
Width and height are whole numbers linked by the original proportions. The output height is recalculated from the width, so rounding can move it by one pixel.
Can Resize Image resize several photos at once?
No. It resizes one image at a time. Select Change image to load the next photo; the quality setting stays, while the size and format start again from the new image.
Your input is processed in your browser without a ToolWorld Online account. Copy or download anything you want to keep before leaving the page.