Resize an Image by Pixels — Free, No Signup
Resize an image to exact pixel dimensions. Type a width or a height, keep the aspect lock on to preserve proportions, and download. The format is preserved, so a transparent PNG stays transparent.
How to do it
- Drop the image onto the upload box.
- Type the exact width or height you need in pixels.
- Leave the lock on to keep the proportions, or turn it off to set both values independently.
- Download the resized file.
Pixels are the only dimension that matters on screen
Image files sometimes carry a DPI or PPI value, and it causes endless confusion. For anything displayed on a screen, that number is ignored completely — a 1000 by 800 image is 1000 by 800 whether its metadata claims 72 DPI or 300 DPI. DPI only becomes meaningful at print time, where it describes how many pixels get packed into each physical inch of paper. If a print shop asks for 300 DPI at A4, what they actually need is roughly 2480 by 3508 pixels. Set the pixel dimensions and the DPI question answers itself.
Aspect lock, and when to turn it off
With the lock on, entering one dimension fills in the other proportionally, so the image cannot be distorted. That is what you want almost always. Turn it off only when you have a deliberate reason to stretch — fitting a fixed banner slot where a little distortion is invisible, or matching a template that demands exact dimensions and you have already cropped to something close. If you need exact dimensions from a differently-shaped source without distortion, crop to the target ratio first, then resize with the lock on.
Downscaling in steps
Reducing an image by a large factor in one jump samples a handful of source pixels and discards the rest, which is why single-pass resizes shimmer on fine repeating detail — brick, fabric, hair, small text. This resizer halves repeatedly instead, averaging each stage into the next so that detail is folded down rather than thrown away. The result is measurably sharper on patterned content and costs nothing extra. You will notice it most going from a full-resolution camera photo down to web size.
Upscaling has hard limits
Enlarging cannot create detail that was never captured. Interpolation looks at neighbouring pixels and guesses what belongs between them, which produces a larger but softer image — and any compression artefacts in the source get enlarged along with everything else. Doubling is usually acceptable for viewing at a distance; beyond that the softness is obvious. If you need a small image to look sharper rather than merely bigger, the image enhancer combines upscaling with sharpening and denoising, which reads better than a plain resize.
What is preserved
The output format matches the input: JPEG stays JPEG, PNG stays PNG with its alpha channel intact, WebP stays WebP. Input is capped at 5 MB and output at 10000 pixels on a side. Nothing is uploaded — the resize happens on your own device using the browser's canvas, so the image never travels anywhere.
Frequently asked questions
Does resizing change the file format?
No. JPEG stays JPEG, PNG stays PNG with transparency intact, and WebP stays WebP.
What is the difference between pixels and DPI?
Pixels are the actual image data. DPI only describes how densely those pixels are printed on paper and is ignored entirely on screen.
How do I resize without stretching?
Leave the aspect lock on and enter only one dimension. The other fills in proportionally so the image cannot be distorted.
Can I make a small image bigger?
Up to 10000 pixels on a side, but upscaling interpolates rather than inventing detail, so the result is larger and softer. Doubling is usually the practical limit.
What dimensions do I need for a 300 DPI A4 print?
Roughly 2480 by 3508 pixels. Set that and the DPI field takes care of itself.
Why does my resized photo look sharper here than elsewhere?
Large reductions are done in successive halving steps rather than one jump, which averages fine detail down instead of aliasing it.