Image resize
Media and filesHow big should your image be?
Resize a photo or picture by width, height or percent. It stays on your device.
What you enter stays on your device while you use this tool. Opening a shared link sends the settings in its address to HowToolbox to prepare the page.
You can also paste an image. Files stay on your device.
Resized to
No image yet
You will see
- New size in pixels
- File size before and after resizing
- The image before and after resizing
The image is resized on your device and is never uploaded. One image at a time, up to 16,384 pixels a side.
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Resize a photo or picture by width, height or percent. It stays on your device.
How to use
- Choose an image from your device, or drop it on the box. It is not uploaded.
- Pick how to set the size: width, height, percent, longest side, or an exact width and height.
- Check the new size and the preview, then download the resized image.
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How it works
An image is a grid of pixels. Resizing makes a new grid with a different number of pixels, and each new pixel is a blend of the nearby old ones. Your browser does this on your own device, so the picture is never sent anywhere.
To keep the proportions, one scale factor is used for both sides: new width ÷ old width. A 4000 × 3000 photo resized to a width of 800 uses a factor of 0.2, so the height becomes 3000 × 0.2 = 600 and the result is 800 × 600. The other side is rounded to a whole pixel. Choose an exact width and height only if you want the proportions to change.
Making an image smaller keeps it sharp; making it larger only stretches what is there and cannot add detail. Very large images (over about 16 million pixels) are refused, because a phone or an older computer may run out of memory. Transparency is kept in PNG, WebP and AVIF; JPEG has none, so it is filled with white.
Worked example
What size does a 4,000 × 3,000 photo become at 800 pixels wide?
- Height = 3,000 × 800 ÷ 4,000 = 600.
The resized photo is 800 × 600 pixels.
Frequently asked questions
Is my image uploaded?
No. The image is opened and resized in your browser and never leaves your device.
Does it keep the proportions?
Yes, unless you choose an exact width and height. With width, height, percent or longest side the other side follows automatically.
Why does a resized photo sometimes get a bigger file?
The file type decides the size. A photo saved as PNG is much larger than the same photo as JPEG or WebP, so choose a lossy type to shrink the file.
Is photo location data copied?
No. The new image is drawn from the pixels only, so camera details and location are left out. The photo's rotation is applied.
Will enlarging a photo restore missing detail?
No. Enlarging adds pixels but cannot recover detail that was not in the original. Check the preview for softness before downloading.
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