Utilities

File Compressor

Shrink images, PDFs, Office files and more in your browser, with the real saving shown.

Photographs and PDFs are what fill up an inbox, and both are usually far larger than they need to be. This decodes each file, re-encodes it at a quality you choose, and reports the actual before and after — never a rename dressed up as a saving. It says plainly which formats it cannot help with and why, rather than accepting everything and reporting a fraction of a percent.

What File Compressor gives you

Everything below is included — no add-ons, no per-app checkout.

JPG, PNG, WebP and GIF images — resized and re-encoded
PDFs, Word, Excel and PowerPoint — the images inside them re-encoded
Text and CSV deflated into a zip; SVG minified
Original and compressed size, and the real percentage saved
Unsupported formats named, with the reason
Runs in your browser — nothing is uploaded

About File Compressor

What it does, how to use it, and where it stops.

Compression removes redundancy. How much there is to remove depends entirely on the format — a photograph has a great deal, a PDF that is mostly text has very little, and a file that is already compressed has almost none. That is why the same tool can take 70% off one file and 2% off the next without anything being wrong.

Why some files shrink and others barely move

Photographs compress well because the eye tolerates detail being discarded. Re-encoding a JPEG or a PNG at a lower quality throws away information a viewer will not miss, and the saving is large.

Formats that are already compressed have nothing left to give. A ZIP, a .docx, a JPEG straight from a phone and an MP4 have all been squeezed once; running them through general compression again typically saves a fraction of a percent, and can make the file marginally larger because of the container overhead.

This is also why zipping a folder of photographs is disappointing while zipping a folder of text is dramatic. Plain text is enormously redundant — repeated words, repeated structure — and deflate exploits exactly that.

What each format does here

Images — JPG, PNG and WebP — are re-encoded at the quality you choose, which is where the largest savings come from. PDFs are handled by re-encoding the images inside them and leaving the text layer untouched, so the document stays sharp and searchable while the photographs stop dominating the size.

Word, Excel and PowerPoint files are ZIP containers underneath. They are unpacked, the embedded photographs are re-encoded, and the container is rebuilt — which is why a deck full of screenshots shrinks substantially and a text-only document does not.

SVG is minified rather than zipped, so the result is still an image you can drop into a browser or a design tool. Plain text is deflated into a .zip, because that is the archive both Windows and macOS open with a double click.

Choosing a quality level

Balanced is the setting to start from: it is chosen to be the point where a photograph still looks right at full size while losing most of its weight. Maximum quality makes a smaller saving and is the right choice for anything being printed or edited further.

Smallest is visibly softer. It is for when a size limit is the constraint — an upload cap, an email attachment, a form that refuses anything over a few megabytes — and the detail matters less than getting the file through.

The percentage saved is measured on the real output, not estimated. Where a file genuinely cannot be improved, it is returned untouched and said so, rather than being re-wrapped so a number can be shown.

Privacy and size limits

Everything runs in your browser. The file is read from your own disk into your own tab, processed there, and handed back — it is never uploaded, never written to a server, and there is nothing to delete afterwards.

The practical ceiling is your own device’s memory rather than an upload limit, which is why large files are workable here but slow on an older phone.

Where people use it

An email attachment over the limit

Compress the PDF or the images and get under the cap without splitting the document up.

A deck heavy with screenshots

Re-encode the pictures inside the .pptx and keep the slides, text and layout exactly as they were.

Photographs for a website

Cut the file size at balanced quality so pages load faster without the images visibly degrading.

A form that rejects your upload

Use the smallest setting to get under a hard limit when the size matters more than the detail.

Tips

• Start at balanced and only move if the result is wrong — most files need nothing else.
• Compress a copy, not your only original. Re-encoding is lossy and cannot be undone.
• Do not re-compress a file you already compressed here. The second pass costs quality and saves almost nothing.
• For a PDF that barely shrinks, the size is the text and fonts rather than images — there is little to remove.

What it will not do

• Video and audio are not processed.
• A file that is already compressed will barely change, and is returned untouched rather than re-wrapped.
• Image compression is lossy. The original quality cannot be recovered from the output.
• Nothing is uploaded, so nothing is stored, shared or recoverable once the tab is closed.

How it works

The things worth knowing before you sign up.

How do I reduce a file size online?

Drop the file in, choose how hard to compress, and download the smaller version. You are shown the original size, the compressed size and the real percentage saved, so you can judge whether the trade is worth it.

Which file types can be compressed?

JPG, PNG and WebP images, which are resized and re-encoded, and PDFs, where the images inside them are re-encoded. Anything unsupported is named explicitly, with the reason, rather than silently skipped.

Will compressing ruin the quality?

That is your choice: maximum quality, balanced, or smallest file. Balanced is usually indistinguishable at normal viewing size; smallest is for when an upload limit is the only thing that matters.

Are my files uploaded anywhere?

No. Compression happens in your browser, so the file never leaves your device.

How much smaller will my file get?

It depends on the original. A photograph from a phone often drops by 70-90% with no visible difference; a PDF that is mostly text may barely move because there is little to remove. The real percentage saved is shown after each run, not estimated.