Calculator
What the Image Cropper does
Image Cropper: cuts the image to a chosen aspect ratio (largest box that fits, anchored to the centre or an edge) or to an exact pixel box you specify. Everything runs in your browser and the file is never uploaded.
Pick a file and the Image Cropper processes it right here in the page. Processing is local, so speed depends on your machine rather than someone else’s server load.
Getting the dimensions right before upload avoids a lot of downstream cropping. The Image Cropper exists to take that particular chore off your hands.
The image is processed on your device and never uploaded, so personal photos stay personal.
Field definitions, the method, and a worked example from the default values are all set out further down the page.
What do the Image Cropper fields mean?
The Image Cropper uses 9 inputs. It opens with a complete example loaded, which is usually the quickest way to understand what a field means.
| Field | What to enter | Default |
|---|---|---|
| Image file | stays on your device | none |
| Crop to | choose from Square (1:1), 4:3, 3:2, 16:9 widescreen, 9:16 story / reel or 4:5 portrait | Square (1:1) |
| Keep | choose from Centre, Top, Bottom, Left or Right | Centre |
| Left offset | measured in px; accepts 0 to 20000 | 0 |
| Top offset | measured in px; accepts 0 to 20000 | 0 |
| Crop width | measured in px; accepts 1 to 20000 | 800 |
| Crop height | measured in px; accepts 1 to 20000 | 600 |
| Export as | choose from PNG, JPEG or WebP | PNG |
| Quality % | accepts 10 to 100 | 92 |
How does the Image Cropper work?
Each output is derived from the inputs above in a single pass; there is no hidden state carried between runs, so the same inputs always give the same result.
Each field is verified before use; failures are reported explicitly rather than swallowed.
What a typical run looks like
You provide: Image file, Crop to, Keep, Left offset, Top offset, Crop width, Crop height, Export as and Quality %
What happens: the file is read into memory by your browser, processed locally, and offered back as a download. It is never uploaded.
You get back: the finished file to download, with a line in the panel saying what was done.
Because the work is local, speed depends on your device rather than our servers, and large files are limited only by available memory.
How to use it
- Choose your file under Image file, or drag it onto the drop area.
- Pick a value for Crop to: the options are Square (1:1), 4:3, 3:2, 16:9 widescreen, 9:16 story / reel or 4:5 portrait.
- Pick a value for Keep: the options are Centre, Top, Bottom, Left or Right.
- Put Left offset in px (0 to 20000).
- Key in Top offset in px (0 to 20000).
- Fill in Crop width in px (1 to 20000).
- Type Crop height in px (1 to 20000).
- Pick a value for Export as: the options are PNG, JPEG or WebP.
- Set Quality % (10 to 100).
- Press Crop.
- Look at Status in the output panel.
- To keep the result, either copy the link or print the page. Both preserve what is on screen.
What this tool does not do
- Re-encoding a lossy format such as JPEG always loses some detail, even at maximum quality.
- EXIF metadata may be dropped during processing, which is usually desirable but is worth knowing.
- It will not warn you that a different tool would suit your question better.
- Garbage in, garbage out: confirm each figure means what you think it does before trusting the result.
- Because everything runs locally, processing speed depends on your device rather than our servers.
Frequently asked questions
Enter Left offset in px, Top offset in px, Crop width in px and Crop height in px. Both the inputs and the result are explicitly labelled, so mixed units cannot slip through unnoticed.
Left offset accepts 0 to 20000 px. Anything beyond those bounds is flagged rather than approximated.
No. The file is read by your browser and processed inside the page. It is never sent to us, which is also why it keeps working offline once loaded.
It is free with no conditions: no sign-up, and no limit on how often you use it.
It is accurate to the method shown. Rounding only affects what is displayed, never what is computed.