JPEG Compressor
Upload forms and email often cap an image at 50 KB, 100 KB or 200 KB. Choose one of those, or your own size, and the JPEG Compressor finds the best-quality JPEG that fits. Or set the quality yourself and compare before and after.
It keeps your pixel dimensions where it can, and says plainly when a size cannot be reached instead of handing you a file over the limit.
Runs in your browser. JPEG Compressor processes your input on your own device. Nothing you enter or upload is sent to a server.
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(opens in a new tab)How to use the JPEG Compressor
- Drop a JPG, PNG or WebP onto the upload area, or click it to pick a file.
- To meet a size limit, pick 50 KB, 100 KB or 200 KB, or choose Custom and type a whole number of KB, then press the Compress button.
- Or skip the target and move the quality and scale sliders to compress by hand.
- Read the result panel: requested size, actual size, whether the target was met, and the output dimensions. Check the preview against the original.
- Download the JPEG.
Supported formats: JPG, JPEG and PNG input; JPEG output.
Compress a JPG to 50 KB, 100 KB or 200 KB
Pick one of the three presets, or choose Custom for any whole number of KB from 1 to 5,000. The tool encodes your image a handful of times, measures the size of each real file, and keeps the best one that fits. It never reports success from an estimate: the figure you see is the size of the JPEG you will download.
Quality comes down first, and the image is only scaled down when quality alone would fall too low. When it finishes, the result panel shows the size you asked for, the real size of the file it made, whether the target was met and the output dimensions, and it says so plainly if the picture had to be made smaller.
What happens depends on the picture. These are typical outcomes, not promises, and your own image may behave differently.
A holiday photo, 3000 × 2000 pixels, about 2 MB, target 200 KB
Input
Choose 200 KB, then Compress
Output
Often fits by lowering quality alone, so the picture keeps its 3000 × 2000 pixels.
The same photo, target 50 KB
Input
Choose 50 KB, then Compress
Output
Usually needs the picture scaled down as well, because quality alone would leave it badly blocky. The panel states the new dimensions.
A 400 × 400 logo saved as a 60 KB PNG, target 50 KB
Input
Choose 50 KB, then Compress
Output
Usually fits easily as a JPEG. Transparent areas are filled with white because JPEG cannot store transparency.
A JPEG that is already 40 KB, target 100 KB
Input
Choose 100 KB, then Compress
Output
Left exactly as it is. A file that already meets the limit is not re-compressed.
Quality, file size and pixel dimensions are different things
JPEG quality is how much fine detail the encoder throws away, on a scale of 1 to 100. It is not a percentage of the file size: quality 50 does not give half the bytes. File size is what you are limited by, measured in KB after encoding, and it depends on the picture as much as on the setting. Pixel dimensions are the width and height of the image. Scaling changes them.
JPEG is lossy, so detail that has been discarded cannot be recovered. A busy photograph with grass, hair or text in it needs far more bytes per pixel than a smooth sky, which is why two images at the same quality can differ many times over in size.
| Control | What it changes | Effect on file size | Effect on the picture |
|---|---|---|---|
| JPEG quality | How much detail is discarded | Lower quality, smaller file | Softer detail, then blocky patches at the low end |
| Image scale | Pixel width and height | Fewer pixels, smaller file | Less resolution, a smaller picture |
| Target size | Both, chosen for you | Fits the limit if it can | Quality first, scaling only when needed |
Why some targets need a smaller picture
A 12 megapixel photo has about 12 million pixels. Squeezed into 50 KB, that is a tiny fraction of a byte for each pixel, far less than JPEG normally needs to keep a photograph looking right. Dropping quality alone to get there gives a heavily blocky result, so the tool lowers quality only as far as a floor of 45, and then reduces the pixel count instead. A shrink of under 10% is not worth the change in size, so in those cases it keeps every pixel and accepts a somewhat lower quality.
The picture is never scaled below 10% of its original width and height. If even that is not small enough, the tool reports that the target was not reached and shows the smallest file it could make, with its real size, so you can decide what to do. Larger targets, a simpler image, or resizing the image yourself first all help.
What KB means here
On this page 1 KB is 1,024 bytes, the same unit every file size shown by the tool uses. So 100 KB is 102,400 bytes. A few upload forms count 1 KB as 1,000 bytes. If a limit is strict, choose Custom and leave a few KB of margin.
The result is usually a little under the target rather than exactly on it, because the tool keeps the highest whole-number quality whose real file still fits.
Which image tool for which limit
- File size is the problem and the image can change shape a little: use this JPEG Compressor.
- The pixel dimensions are the problem, for example a form that wants 800 pixels wide: use the Image Resizer.
- Several JPG, PNG or WebP files that must keep their own formats: use the Image Compressor.
- A different format, such as turning a PNG or WebP into a JPG without aiming for a size: use the Image Converter.
Things worth knowing
- Compression is lossy: the original detail cannot be recovered from the compressed file.
- Very large images may take a moment to process, and are limited by your device's available memory. If your browser cannot encode an image, the tool tells you instead of failing silently.
- A target is met only when the finished file's real size is at or under it. The tool never scales a picture below 10% of its width and height, and it reports a target as not reached, with the smallest result it could make, when that is not enough.
- A JPEG that is already at or under your target is left exactly as it is, with its original data untouched.
- This tool works on one image at a time and always outputs a JPEG, even from a PNG or WebP source, so any transparent area is filled with white, and it offers scaling and a target file size. To compress several JPG, PNG or WebP images at once and keep each one's format and dimensions, use the Image Compressor.
Frequently asked questions
How do I compress a JPG online?
Open the tool, choose your image, then either pick a target such as 100 KB and press Compress, or move the quality slider and compare the preview with the original. Download the JPEG when the size and look are right. Everything happens in your browser.
How do I compress a JPG to 100 KB?
Choose your image, select the 100 KB preset and press Compress. The result panel shows the real size of the file it made and whether it is within 100 KB. For a photo this often needs quality lowered, and sometimes the pixel size reduced too, and the panel tells you which.
Can every image be compressed to 50 KB?
No. A small or simple image usually can. A large, detailed photo may need to be scaled down a lot, and a very small target may be out of reach even at the smallest size the tool allows. When that happens the tool says the target was not reached and shows the smallest file it could make, rather than claiming success.
Will the tool change my image's dimensions?
Only if it has to. It lowers JPEG quality first, down to a floor, and scales the picture down only when quality alone cannot reach the size you asked for. The result panel always shows the output dimensions, and says when they changed and why.
Why is my result a little under the target?
JPEG quality moves in whole steps and each step changes the file size by a few KB. The tool keeps the highest quality whose real file still fits, so the result lands just under the limit.
What does KB mean on this page?
1 KB is 1,024 bytes, so 100 KB is 102,400 bytes. If a site counts 1 KB as 1,000 bytes and its limit is strict, use the Custom option and leave a few KB of margin.
Does compressing a JPEG reduce its quality?
Yes. JPEG compression is lossy, so some detail is always discarded. At high quality settings the difference is usually hard to see at normal viewing size, but it is a real trade-off rather than a free saving. Compare the preview against the original before downloading.
How small will my file get?
It depends on the image. Photographs with lots of gradients and texture compress a great deal; flat graphics, screenshots and images that have already been compressed once have much less to give. The tool shows you the actual size of your file, and with a target it tells you whether the target was met.
Is my image uploaded anywhere?
No. The compression runs in your browser using a canvas element, so the file stays on your device and is never sent to a server.
Can I compress the same image twice?
You can, but it is rarely a good idea. Each pass discards more detail permanently, and the second pass usually saves far less than the first. Start from the original file whenever you can.
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