Compress a JPEG to the size you need
Set a target size, add your JPG or JPEG files, and each one comes back at the highest quality that fits. Nothing is uploaded — the work happens in this tab.
Compress a JPEG
What the quality number really controls
JPEG does not store pixels. It splits the image into eight-by-eight blocks, describes each block as a set of frequency patterns, and then throws away the patterns your eye is least likely to miss. The quality setting decides how aggressively it discards them.
This is why quality 90 and quality 80 can differ by 40 percent in file size while looking nearly identical, and why quality 30 and quality 20 look very different but barely differ in size. The scale is not linear, which is exactly why this tool searches for the right value instead of letting you guess at one.
Each re-compression costs you something
Every time a JPEG is decoded and re-encoded, the block artefacts from the previous round are treated as real detail and preserved, while new artefacts are added on top. Do it enough times and the image visibly falls apart.
Practically: compress once, from the best original you have. If a result is not small enough, go back to the original and pick a smaller target rather than compressing the output again. The tool always works from the file you gave it, never from a previous result.
JPEG is the safe choice for forms
Upload validators are conservative. A form that says it accepts images very often means JPG and PNG only, and will refuse WebP, HEIC or AVIF regardless of size. When the destination is a form, leave the output as JPEG.
The exception is a very small target. Below about 30 KB, WebP holds detail visibly better than JPEG — worth switching to if you have confirmed the form accepts it.
Questions people ask
What is the difference between JPG and JPEG?
None. They are the same format with two spellings of the extension, a leftover from when Windows allowed only three characters. Either extension will be accepted anywhere the other is.
Can I compress a JPEG without any quality loss at all?
Not with this tool. Truly lossless JPEG optimisation exists, but it typically saves only five to ten percent — nowhere near enough to hit a specific KB target.
Does this convert my JPEG to another format?
Not unless you ask. With the format set to JPEG the output stays a JPEG. Choosing WebP or PNG converts it, and the file extension changes to match.
Why did my progressive JPEG get bigger?
Browser encoders write baseline JPEG, which is slightly larger than progressive at the same quality. If your original was already well optimised and close to the target, the tool will tell you it cannot improve on it.
Other sizes and tools
Last reviewed 2026-09-04. Also searched as: compress jpg, jpeg compressor, jpg size reducer, compress jpg to kb.