Crop Image

A worked example, with the real numbers

Say you load a 4032 x 3024 photo straight off a phone. The preview is capped at 640 px wide and 520 px tall, so it is displayed at 640 x 480 and every preview pixel stands for 6.3 actual pixels. That ratio is the scale factor, and the tool keeps it so your crop can be cut from the original file rather than from the shrunken preview.

The starting box covers 80 per cent of the frame, centred, which here is 512 x 384 in preview terms. Export that untouched and you get a 3226 x 2419 file. Switch the ratio dropdown to 1:1 first and the box is rebuilt as a centred square, 384 x 384 on screen, giving a 2419 x 2419 export. The line under the canvas always shows the true output size next to the original size, so you can check before you commit.

Because one preview pixel equals 6.3 real ones here, the finest adjustment you can make by dragging is about six pixels of the source. That is invisible in a holiday photo and matters if you are trying to land on an exact number such as 1200 x 800.

How the box responds to your pointer

There are eight grab points: four corners and four edge midpoints. Grab a corner and the opposite corner stays pinned. Grab a top or bottom edge and the box grows vertically from the edge you did not touch. Press inside the shaded rectangle and you move the whole box without resizing it, and the box is clamped so it can never run past the edge of the picture.

Press anywhere outside the box and you start drawing a brand new rectangle from that point, which surprises people the first time. If you did not mean to, hit Reset box and the 80 per cent default comes back.

With a ratio locked, the tool keeps the width you drag and recalculates the height from it on corner handles. On the side handles it does the reverse and re-centres the box on the axis you are not dragging, so a locked crop tends to stay put rather than drift into a corner. The smallest box allowed is 12 preview pixels on either side.

Which ratio for which job

1:1 suits profile pictures, marketplace listings and Instagram grid posts. 4:3 matches most camera sensors and standard photo prints such as 6 x 4 inch. 16:9 is the shape of video thumbnails, slide decks and desktop wallpapers. 9:16 is the vertical full-screen shape used by Stories, Reels and Shorts. If none of those fit, the custom fields take any pair of numbers, for example 3 and 2 for a 35 mm print or 85 and 55 for a business card.

Things that catch people out

Cropping does not resample. The pixels inside the box are copied across one for one, so a crop is exactly as sharp as the original was. What you do lose is total resolution: crop a 12 megapixel photo down to a quarter of its area and you now have a 3 megapixel image, which is still fine on screen but will print smaller.

Exporting a photographic crop as PNG will very often produce a much larger file than the JPG you started with, sometimes four or five times bigger, because PNG stores every pixel losslessly and photographs are full of noise. Use PNG for screenshots, logos and anything with flat colour or transparency. Use JPG for camera photos, which the tool encodes at 0.92 quality with no dial to adjust.

The tool reads JPG, PNG and WebP. HEIC files from an iPhone will be rejected because browsers cannot decode them natively, and the ratio presets are stored to four decimal places, so a locked 16:9 crop can land a single pixel off a perfect ratio after rounding.

Other tools that pair with this one

To force the result to an exact pixel size after cropping, run it through the image resizer. If the photo is sideways, straighten it first with rotate and flip, because cropping a rotated image twice wastes pixels. For a strict file size limit rather than a shape, use compress to a target KB. To turn the cropped result into WebP or PNG in a batch, use the image converter.

Frequently asked

Can I crop to an exact size such as 800 x 600?

Not directly. The readout tells you the live output size, so you can get close by hand, but dragging is limited by the preview scale. Lock the 4:3 ratio, crop roughly, then set 800 x 600 precisely in the resizer.

Does cropping make the picture blurry?

No. The selected region is copied at its original resolution with no scaling applied, so detail is unchanged. Only the pixel count of the whole file goes down.

Why is my cropped PNG larger than the original photo?

PNG compression is lossless and does not suit photographic detail. A crop of a 2 MB camera JPG can easily save as an 8 MB PNG. Choose JPG in the format dropdown for photos.

Does it work with a finger on a phone?

Yes, the canvas uses pointer events, so touch drags work for both moving and resizing. The handles are 10 pixels across, which is small for a fingertip, so pinch the page to zoom in before grabbing a corner.

Why was my iPhone photo rejected?

It is almost certainly a HEIC file. Convert it with the HEIC to JPG tool and then crop the JPG.