Resize Image
Resize images to exact pixel dimensions with precision control.
How it works
Upload Image
Select the image you want to resize.
Set Dimensions
Enter the desired width and height in pixels.
Download
Download your resized image in the original format.
About This Tool
JustConvert's Image Resize tool gives you precise control over image dimensions. Enter exact values in pixels, centimetres, millimetres, or inches — specify only one dimension to automatically maintain the aspect ratio, or enter both to force custom sizing. Lanczos resampling ensures the highest quality when downscaling.
Common use cases include resizing photos for social media profile pictures, optimising images for email attachments, preparing visuals for website headers, or printing at a specific physical size. The output format matches your original image format.
- check_circleResize in pixels, cm, mm, or inches
- check_circleAuto aspect ratio lock when only one dimension is set
- check_circleLanczos resampling for sharp downscaling
- check_circleOutput retains the original image format (JPG, PNG, WebP)
- check_circleNo quality degradation beyond the resampling itself
- check_circleSupports images up to 50 MB
Resize, crop, or compress — which do you actually need?
Three tools solve three different "my image is wrong" problems. Resize changes how many pixels wide and tall the image is — use it to fit a layout, a profile slot, or a print size. Crop changes what is in the frame by trimming the edges, so reach for Image Crop when you want a square headshot out of a wide photo. Compress leaves the dimensions alone and only shrinks the file in KB, which is the job of Image Compress. Many real tasks use two in sequence: resize a giant photo down to web dimensions, then compress it to meet an upload limit.
Keeping the result sharp
Enter just one dimension — width or height — and the other is calculated for you, so the image keeps its proportions and never looks stretched. Enter both only when you deliberately want a fixed box and can accept some squashing. Direction matters too: downscaling (making an image smaller) stays crisp because the tool uses Lanczos resampling, the same high-quality method desktop photo editors use. Upscaling (making it larger than the original) can only invent pixels that were never captured, so a small image blown up will look soft — always start from the highest-resolution copy you have.
Common pixel sizes worth knowing
| Where the image goes | Typical size (pixels) | Note |
|---|---|---|
| Instagram square post | 1080 × 1080 | 1:1 aspect ratio |
| WhatsApp or profile picture | 640 × 640 | Square, kept small |
| Full-HD header or wallpaper | 1920 × 1080 | 16:9 widescreen |
| Website content image | 1200 wide | Leave height blank to keep proportions |
Frequently Asked Questions
How do I resize an image without losing quality? expand_more
Upload your image, enter the target width or height (entering just one preserves the aspect ratio), and click Process. The tool uses Lanczos resampling, which is the highest-quality algorithm for reducing image size.
Can I resize an image to exact pixel dimensions? expand_more
Yes. Enter both width and height values. The image will be stretched or squeezed to match the exact dimensions you specify, which may alter the aspect ratio.
Which unit types are supported? expand_more
You can resize using pixels (px), centimetres (cm), millimetres (mm), or inches. The DPI field allows accurate conversion from physical units to pixels.
Will resizing change the image file format? expand_more
No. The output image uses the same format as the original upload. A JPG stays JPG, a PNG stays PNG.
What is the maximum image size I can resize? expand_more
Files up to 50 MB are supported. Very high-resolution images (20+ megapixels) may take a moment longer to process.