Free offline file compressor for Windows Squash big files.
Keep them yours.

Yes. Crunchy is free to download and use: no ads, no account, no trial and no paywalled levels.

No. Crunchy compresses every file locally on your PC, so your files never leave it. It only goes online to check a tiny update file (at launch and once a day while it's open), to download FFmpeg, its video and audio tools, when you accept them (the setup and the app offer them), and, when you choose to, to download an update. By default it writes new, smaller copies and leaves your originals alone; if you switch on Replace originals, the old files go to the Recycle Bin so you can always get them back.

Privacy statement

Use Crunchy's Target size. Add the PDF, switch on Target size, enter 25 MB and press Crunch. Crunchy first compresses the file at your chosen level; if it is still too big, it tries stronger settings, up to seven passes, and keeps the gentlest version that fits, as close under 25 MB as it can get. If the goal is out of reach within Crunchy's quality floors, it goes as far as its last-resort limits; if even that isn't small enough, it keeps the smallest version and tells you the smallest size possible. The Email preset does this in one click with a 20 MB target, the Balanced level and metadata stripped. Gmail's attachment limit is 25 MB. From the command line: crunchy --target 25MB file.pdf

Compress PDFs

Crunchy compresses PDF (.pdf), Word (.docx .docm .dotx .odt), Excel (.xlsx .xlsm .ods), PowerPoint (.pptx .pptm .ppsx .odp), images (.png .jpg .jpeg .jfif .webp .gif .tif .tiff .bmp), SVG (.svg .svgz) and, since version 2.0, videos (.mp4 .m4v .mov .mkv .webm .avi .wmv .flv .ts .mts .m2ts .3gp .mpg .mpeg) and audio (.mp3 .m4a .aac .wav .flac .ogg .oga .opus .wma .aiff .aif .aifc .ape .wv .amr .mka). Anything else you drop in is copied to the output unchanged, unless you switch that off.

PDFs Office files Images Videos Audio

Open it in Crunchy on the Balanced or Maximum level. Crunchy detects pages that are black-and-white text or handwriting and stores them as sharp 1-bit CCITT G4 images, which are far smaller than colour or greyscale scans. In testing for version 1.0.1, a 247 MB scanned book shrank by about 88% on Balanced and 92% on Maximum. Pages with photos, shading or colour stamps stay in colour, and the Light level leaves scans as they are.

How PDF compression works

Add it to Crunchy and compress it on Balanced. Crunchy resizes each picture to the size it is actually shown at on the slide or page, turns photos saved as PNG, BMP or TIFF into JPEG, compresses embedded charts and documents too, and repacks the file. Photo-heavy decks often shrink by 60–90%. It works with .pptx, .pptm, .ppsx, .docx, .docm, .dotx, Excel files and the OpenDocument formats.

Compress Office files

Crunchy removes EXIF, GPS location and XMP data by default whenever it compresses a photo (the Strip metadata option), and it rotates the picture upright first so nothing ends up sideways. Add your photos and press Crunch: the copies carry no location or camera data. To keep metadata, switch Strip metadata off, choose the Archive preset, or use --keep-metadata on the command line.

Compress images

With Crunchy, it depends on what's inside the file. Scanned PDFs shrink the most: a 247 MB scanned book shrank by about 88% on Balanced. Photo-heavy PowerPoint decks often shrink by 60–90%, PNG screenshots are often about 70% smaller, and camera JPEGs often by half or more. For videos it depends on how they were recorded and on the resolution, frame rate and codec you pick. A WAV recording typically ends up around half its size or less as lossless FLAC (it depends on the sound), and about a seventh of it as 192 kb/s AAC on Balanced. Files that are already well compressed may barely move; if Crunchy can't make a file smaller, it keeps the original bytes and marks it Already optimized.

Yes. Crunchy works on every CPU core and compresses the images inside big PDFs in parallel; for the 1.0.2 release, a 268 MB PDF took 16 seconds instead of 66. Images up to 500 megapixels are supported too. Pages that contain photos or colour are kept in colour; only pages that really are black-and-white text are converted.

Yes. Since version 2.0, Crunchy compresses MP4, MOV, MKV, WebM, AVI, WMV, FLV, TS/MTS/M2TS, 3GP, MPG and M4V videos on its Videos page. Start from a preset (Discord, Email, Share, Archive or Smallest) or set it yourself: keep the original resolution or pick 2160p (4K), 1440p (2K), 1080p (Full HD), 720p (HD), 480p (SD) or 360p (only sizes up to the source's, so nothing is upscaled), cap the frame rate at 60 or 30, choose H.264, H.265 or AV1, and choose a speed. Every audio track is kept, Target size works for videos too, and a video that doesn't get smaller is kept as it was. Audio files have their own Audio page, from the same release.

Compress videos Compress audio

To a Crunchy folder inside your Downloads folder, unless you choose otherwise. A folder you drop keeps its structure inside it, for example Downloads\Crunchy\Videos\Rainbow Six Siege\clip.mp4. To change the default for good, pick another folder in Settings › Saving. To change it for one batch only, use the Save to button on the Files, Videos or Audio page; the next batch starts from your default again. From the command line, -o picks the folder (the default is the same Crunchy folder in Downloads). Your originals stay where they are unless you switch on Replace originals.

Command-line guide

Yes. Since 2.0.1, each of the Files, Videos and Audio pages remembers its own custom compression choices, even after you clear the queue, start a new batch or restart the app. Settings still holds your defaults, and changing them does not overwrite custom page choices. Click Reset to default below the custom-options hint to return that page to the latest Settings defaults. A save folder picked on a compression page is still for that batch only.

Crunchy has one page for documents and images (Files), one for videos and one for audio, and each shows only its own options: the Files page has presets, Output (separate files or one ZIP) and Shrink images; the Videos page has presets, resolution, frame rate, codec and speed; the Audio page has the format and Allow mono. Whatever you drop, paste or send to Crunchy is sorted by kind: a drop of only videos opens the Videos page, and a mixed drop is split across the pages, with a note saying where each part went. Ctrl+1, Ctrl+2 and Ctrl+3 switch between them (Ctrl+4 is History, Ctrl+5 Settings, Ctrl+6 About). Only the Files page can pack results into a ZIP.

Quality comes from the level (Light looks like the original, Balanced is the everyday mix, Maximum makes the smallest files) plus the resolution, frame rate and codec you pick. Speed decides how long it takes and where it runs: Faster and Fast use your graphics card (quick, bigger files; Fast uses its best quality setting), while Balanced and Best use the processor, which is slower and makes much smaller files, with Best the slowest. Fast is the default, and the processor takes over when the graphics card can't do it. If you just want a good result, pick a preset. From the command line, -s faster|fast|balanced|best sets it (fast by default), and --cpu never uses the graphics card.

Which settings to use

Presets on the Videos page set several options at once. Discord: every video under 10 MB, 720p, 30 fps, H.264. Email: every video under 25 MB, 720p, H.264. Share: 1080p, H.264, Balanced level and speed, so it plays on every phone, TV and website. Archive: the original resolution and frame rate, H.265, Light and the Best speed, for visually lossless archiving. Smallest: 720p, 30 fps, AV1, Maximum and the Best speed. Change any option afterwards and the preset switches back to Custom.

Video presets

Yes, as far as the video allows. Switch on Target size and type the size you need, for example 100 MB. Crunchy works out the bitrate that fits, and if that would leave too few bits for the resolution you chose, it steps the resolution down by itself (never above the one you chose) so the picture stays as sharp as it can. A target never lowers the frame rate by itself. If even the smallest picture can't reach the size, Crunchy keeps its smallest result and marks it over target.

Which settings to use

Yes. Since version 2.0, Crunchy compresses MP3, AAC/M4A, WAV, FLAC, Ogg Vorbis, Opus, WMA, AIFF, APE, WavPack, AMR and MKA files. On Light it is lossless: WAV becomes FLAC with every sample kept exactly. On Balanced and Maximum, WAV and FLAC become AAC (.m4a), or MP3 or Opus if you pick them, while MP3, AAC, Ogg and Opus files keep their format and are only re-encoded when that really saves space, because re-encoding a lossy file at a similar bitrate only costs quality. Tags and cover art are kept, and Target size works for audio too.

Compress audio

Yes. Point Crunchy at your recordings folder, for example Videos, which holds a sub-folder per game (the layout NVIDIA ShadowPlay / the NVIDIA App, Steam and OBS use). Crunchy lists the videos grouped by game, recognizes the ones it already compressed, and lets you tick whole games or single clips. The results keep the same structure, for example Downloads\Crunchy\Videos\Rainbow Six Siege\clip.mp4. A watch folder on the same folder compresses new recordings automatically, even in a new game's folder. NVIDIA recordings with separate game and microphone audio keep both tracks.

Recordings folder

No. The setup contains Crunchy itself. Video and audio compression run on FFmpeg, which is too big to fit inside the setup, so once Crunchy is installed the setup's last page offers to download it (about 46 MB) in the background. You can say no; Crunchy then offers the download again when you add a video or audio file, and Settings › Video and audio tools always has it. Compressing files never needs the internet.

About the video and audio tools

FFmpeg is a free, open-source (GPL) video and audio toolkit, and Crunchy uses it to compress videos and audio. It runs as a separate program next to Crunchy. Crunchy checks for updates at launch and once a day while it's open; when a newer FFmpeg is available it asks first, then downloads it, checks its SHA-256 and installs it without reinstalling Crunchy. You can also run crunchy --deps to see the installed version and crunchy --update-deps to update it. FFmpeg's licence and a link to its source code ship with Crunchy and are on its About page.

Open-source credits

Not yet. Crunchy is free to use, but its source code isn't public yet. It's built on open-source libraries (Python, Qt/PySide6, Pillow, pikepdf/qpdf, lxml, scour) and uses FFmpeg for videos and audio; their licenses ship with the app.

Open-source credits

Crunchy runs on Windows 10 and Windows 11, 64-bit (x64). It installs just for your user account, so it doesn't need admin rights.

Crunchy isn't code-signed yet (certificates are expensive for an indie app), so SmartScreen may say it "protected your PC" the first few times. Click More info, then Run anyway. If you want to be sure the file is genuine, compare its SHA-256 with the one on the download page.

SmartScreen walkthrough

By default Crunchy copies them into the output unchanged, so a folder you drop comes out complete. You can switch that off to only get the compressed files.

Yes. Run crunchy with files or folders and options such as --level maximum or --target 25MB, for example: crunchy --level maximum --target 25MB file.pdf. Tick the optional Add Crunchy to PATH box in the installer and it works from any PowerShell or Command Prompt window. It behaves like any other command: the prompt waits for it to finish and exit codes work, which makes it easy to script.

Command-line guide

Yes. Crunchy has a full Arabic interface with a right-to-left layout, alongside English. Switch languages from the language switcher in the app.

Crunchy checks a small manifest on this site, /update/latest.json, at launch and once a day while it's open. When a new version is out it offers to download it, verifies the SHA-256 checksum and runs the installer for you. When only FFmpeg, the video component, has a newer version, Crunchy asks and then updates it in place, without a reinstall.

Verify your download