Does AutoCrop upload my images?

No. Every image is decoded and cropped by your own browser using the Canvas API. There is no upload endpoint and no image storage, so your files are never transmitted, seen or logged.

How does it know where to crop?

It reads the alpha channel of every pixel and finds the smallest rectangle containing all pixels more opaque than the threshold. That rectangle becomes the new image, so fully transparent margins disappear.

Why is there still space around my icon after cropping?

Almost certainly a soft drop shadow or glow. Those effects fade out over dozens of pixels and the outermost ones are still technically visible, so the crop keeps them. The blue outline on the original preview shows exactly what was detected. Raise the transparency threshold to cut off that faint edge — around 40 to 100 removes a typical shadow halo.

What does the transparency threshold do?

It sets how opaque a pixel must be to count as content. At the default of 5, anything above alpha 5 of 255 is kept, which preserves even the faintest antialiasing. Raising it trims more of the soft edge; lowering it to 0 keeps every pixel that is not perfectly transparent.

Does it work with JPG?

JPG cannot store transparency, so there is no transparent margin to detect. AutoCrop will tell you an image has no transparent pixels rather than guess at a background colour. Automatic cropping works with PNG and transparent WebP.

Can I add space around the result?

Yes. The padding control adds 0 to 500 transparent pixels to all four sides of the cropped image, and the preview updates immediately.

Can I crop several images at once?

Yes. Drop or select multiple files and each is cropped independently to its own content bounds. Download them one by one or all together as a ZIP.

What is the maximum file size?

The limit is 50 MB per image, and up to 16,384 pixels on either side — the point where browser canvas support becomes unreliable.

Does cropping reduce image quality?

No. The visible pixels are copied across unchanged and re-encoded as lossless PNG, so nothing is resampled or recompressed. Only empty margin is discarded.

Why is the cropped PNG sometimes a larger file than the original?

Your original was probably compressed by an optimiser such as pngquant or ImageOptim. The browser re-encodes with standard PNG settings, which can be less aggressive even though the image is smaller in pixels. Run the result through an optimiser if file size matters.

Yes. It is free, needs no account and adds no watermark.

Automatically remove empty space from your images

Upload an image and AutoCrop trims the transparent area around it automatically. Free, instant, and your images never leave your device.

Drop image here

PNG, WebP or JPG · up to 50 MB · you can also paste from the clipboard

Your images are processed locally in your browser.

How does AutoCrop work?

A PNG exported from a design tool usually keeps the whole artboard. The logo or icon ends up floating in the middle of a large transparent rectangle, which throws off every layout it is later dropped into — it looks smaller than its neighbours, refuses to centre properly, and carries dead pixels into every build.

AutoCrop finds the real edges of your content and discards the rest. Your file is decoded into a canvas and read back as raw pixel data. Every pixel's alpha value is compared against the transparency threshold, and the smallest and largest coordinates that clear it become the bounding box of the visible content. A new canvas is created at exactly that size, the region is copied across, your padding is added, and the canvas is exported as a lossless PNG.

The scan runs in horizontal strips rather than reading the whole image at once, so a 10,000-pixel-wide file needs a few megabytes of working memory instead of hundreds, and the page keeps repainting while it works. All of it happens in your browser through the Canvas API — there is no upload step, no queue, and no server that has to be trusted.

How to remove transparent space from a PNG

1
Upload your PNG
Drag a file onto the dropzone, choose one from your device, or paste an image straight from the clipboard. Nothing is uploaded — the file is read locally.
2
AutoCrop detects the visible area
The alpha channel of every pixel is scanned to find the exact bounding box of your content. A blue outline on the original preview shows what was found.
3
Adjust padding and threshold if needed
Add up to 500 px of transparent margin back, or raise the transparency threshold to cut off the faint edge of a drop shadow. The preview updates as you change either.
4
Download the cropped image
You get a lossless PNG named after the original file, so logo.png downloads as logo-cropped.png. With several images, download them all as a ZIP.

Why a crop can look like it did not go far enough

This is the most common surprise, and it is not a bug. Drop shadows, outer glows and soft edges fade out gradually over dozens of pixels. The outermost of those pixels are effectively invisible to you — an alpha value of 2 or 3 out of 255 — but they are not transparent, so a correct bounding box has to include them.

Here is a real 340 × 340 px icon: a dark disc roughly 216 px across with a soft shadow offset down and to the left. The same image, scanned at different thresholds:

Bounding box detected on one 340 × 340 px shadowed icon.
Threshold	Detected box	What survives
alpha > 0	282 × 288 px	every non-zero pixel, including the invisible tail
alpha > 5 (default)	262 × 270 px	the entire shadow, down to the last faint pixel
alpha > 48	224 × 240 px	most of the shadow trimmed away
alpha > 96	216 × 224 px	the visible disc only, shadow clipped

So a 20-pixel margin of checkerboard around your icon is usually the shadow, not a failed crop. Two things in the interface make this visible: the blue outline drawn on the original preview shows exactly what was detected, and each preview frame is sized to its own image's aspect ratio, so any checkerboard you see is genuine transparency rather than unused space in the panel.

Which formats can be cropped

Format	Transparency	What AutoCrop does
PNG-32 / PNG-24	Full 8-bit alpha	Full automatic crop. This is the ideal input.
PNG-8 (indexed)	One transparent index, or 8-bit alpha	Full automatic crop. Edges are hard rather than soft, so the box is exact. More on PNG variants
WebP	Lossless or lossy alpha	Full automatic crop. Lossy alpha can leave a faint halo — see the WebP notes
JPG / JPEG	None	Accepted, but there is no transparent margin to find. AutoCrop says so instead of guessing at a background colour.

Output is always PNG. It is lossless, universally supported, and the only common format that can carry the transparency you started with plus any padding you add.

What people use this for

Logos exported from Figma, Sketch, Illustrator or Canva that keep the full artboard.
Icon sets where every file must be tight to its own content before being packed into a sprite sheet or icon font.
App and store icons that a submission process rejects for having transparent padding.
Product shots already cut out from their background, ready to be laid out on a page.
Stickers and emoji, where transparent margin wastes the tiny display size available.
Rendered 3D assets and screenshots saved on an oversized transparent canvas.
Trimming exports before committing them to a repository, so no dead pixels ship.

Your images never leave your device

All image processing happens locally in your browser. There is no upload API, no temporary storage bucket and no processing queue — the file is read by JavaScript, drawn onto a canvas, and the result handed straight back to you as a download.

That matters for unreleased logos, client work under NDA, internal screenshots and anything else you would rather not hand to a stranger's server. It also means the tool costs almost nothing to run, which is why it can stay free. See the privacy policy for what analytics does and does not record.

Frequently asked questions

Does AutoCrop upload my images?: No. Every image is decoded and cropped by your own browser using the Canvas API. There is no upload endpoint and no image storage, so your files are never transmitted, seen or logged.
How does it know where to crop?: It reads the alpha channel of every pixel and finds the smallest rectangle containing all pixels more opaque than the threshold. That rectangle becomes the new image, so fully transparent margins disappear.
Why is there still space around my icon after cropping?: Almost certainly a soft drop shadow or glow. Those effects fade out over dozens of pixels and the outermost ones are still technically visible, so the crop keeps them. The blue outline on the original preview shows exactly what was detected. Raise the transparency threshold to cut off that faint edge — around 40 to 100 removes a typical shadow halo.
What does the transparency threshold do?: It sets how opaque a pixel must be to count as content. At the default of 5, anything above alpha 5 of 255 is kept, which preserves even the faintest antialiasing. Raising it trims more of the soft edge; lowering it to 0 keeps every pixel that is not perfectly transparent.
Does it work with JPG?: JPG cannot store transparency, so there is no transparent margin to detect. AutoCrop will tell you an image has no transparent pixels rather than guess at a background colour. Automatic cropping works with PNG and transparent WebP.
Can I add space around the result?: Yes. The padding control adds 0 to 500 transparent pixels to all four sides of the cropped image, and the preview updates immediately.
Can I crop several images at once?: Yes. Drop or select multiple files and each is cropped independently to its own content bounds. Download them one by one or all together as a ZIP.
What is the maximum file size?: The limit is 50 MB per image, and up to 16,384 pixels on either side — the point where browser canvas support becomes unreliable.
Does cropping reduce image quality?: No. The visible pixels are copied across unchanged and re-encoded as lossless PNG, so nothing is resampled or recompressed. Only empty margin is discarded.
Why is the cropped PNG sometimes a larger file than the original?: Your original was probably compressed by an optimiser such as pngquant or ImageOptim. The browser re-encodes with standard PNG settings, which can be less aggressive even though the image is smaller in pixels. Run the result through an optimiser if file size matters.
Is AutoCrop free?: Yes. It is free, needs no account and adds no watermark.

How does AutoCrop work?

How to remove transparent space from a PNG

Upload your PNG

AutoCrop detects the visible area

Adjust padding and threshold if needed

Download the cropped image

Why a crop can look like it did not go far enough

Which formats can be cropped

What people use this for

Your images never leave your device

Frequently asked questions

Related