01 — Ranking
The 5 best options, ranked
7-Zip
7-zip.org
4.8Open-source archiver for Windows with a high compression ratio using its 7z/LZMA2 format.
- Best for
- Archiving folders, backups, source code and logs, plus opening RAR, ZIP, TAR and ISO files.
- Free plan & limits
- Free and open source (LGPL), with no limits and no ads. The 7z format is typically 10–40% smaller than ZIP on text-heavy data. Supports AES-256 encryption and splitting archives into volumes. Windows only, with command-line ports for macOS and Linux (7zz).
Squoosh
squoosh.app
4.6Google's image compressor that runs entirely in your browser.
- Best for
- Web developers optimizing hero images, with a side-by-side quality preview.
- Free plan & limits
- Free and unlimited. Images are processed locally and never uploaded. Converts to WebP, AVIF, MozJPEG or OxiPNG, with resize and quality sliders. Handles one image at a time; for batches, use the Squoosh CLI or Sharp.
TinyPNG / TinyJPG
tinypng.com
4.5Drag-and-drop smart lossy compression for PNG, JPG and WebP.
- Best for
- Non-technical users compressing a small batch of images for a website or email.
- Free plan & limits
- Up to 20 images at a time, each up to 5 MB, on the free web version. PNG files often shrink by 50–80% with little visible quality loss. The API includes 500 free compressions per month, and larger files and bulk use require Pro.
PDF24 Compress PDF
tools.pdf24.org
4.5Free PDF compressor with adjustable DPI and image quality.
- Best for
- Getting scanned or image-heavy PDFs under email (25 MB) or upload-portal limits.
- Free plan & limits
- Free and unlimited, with no account, and files are deleted after 1 hour. Image-heavy PDFs typically shrink by 40–80% at 150 DPI. Text-only PDFs gain little. An offline version is included in PDF24 Creator for Windows.
HandBrake
handbrake.fr
4.6Open-source video transcoder with presets for every common device and platform.
- Best for
- Shrinking screen recordings, phone videos and exports before you upload or archive them.
- Free plan & limits
- Free and open source for Windows, macOS and Linux, with no watermark. Re-encoding to H.265 (HEVC) or AV1 typically produces files 30–50% smaller than H.264 at similar quality. Phone videos often shrink by 50–80% at 1080p with RF 22–24. Encoding is slow without hardware acceleration.
02 — Comparison
Side by side
Scroll sideways to see every tool. The first column stays pinned.
| Feature / Criterion | 7-Zip | Squoosh | TinyPNG | PDF24 | HandBrake |
|---|---|---|---|---|---|
| File types | Any (archives) | Images | PNG / JPG / WebP | Video | |
| Compression type | Lossless | Lossy or lossless | Smart lossy | Lossy (images in the PDF) | Lossy (re-encode) |
| Typical reduction | 10–40% vs ZIP (text) | 50–80% | 50–80% (PNG) | 40–80% (image PDFs) | 30–80% |
| Free limits | None | None (one image at a time) | 20 images × 5 MB | None | None |
| Runs locally (private) | Yes | Yes (in the browser) | No (upload) | Online or desktop | Yes |
| Platforms | Windows (+ CLI ports) | Any browser | Any browser | Browser / Windows | Windows / macOS / Linux |
03 — Guide
How to compress files for free step by step
Identify what kind of data you have
Text, CSV, logs, code and uncompressed BMP or WAV files zip well (often 50–90% smaller). JPG, PNG, MP4, MP3, DOCX, XLSX and PDF are already compressed, so zipping saves about 0–3%. Shrinking those means re-encoding them with a format-specific tool.
Archive folders with 7-Zip
Right-click → 7-Zip → Add to archive. Choose the 7z format with 'Ultra' level for the smallest file, or ZIP for maximum compatibility (Windows and macOS open ZIP without extra software). Set an AES-256 password and enable 'Encrypt file names' for sensitive data.
Re-encode images to modern formats
In Squoosh, convert to WebP (quality 75–80) or AVIF (quality 50–60) and resize to the largest size actually displayed, for example 1600 px wide for a blog hero image. Resizing usually saves more than any quality setting.
Compress PDFs and videos with the right presets
PDF: in PDF24, choose 150 DPI and image quality 75% for on-screen reading, or 300 DPI for print. Video: in HandBrake, use the 'Fast 1080p30' preset, switch the encoder to H.265 and set RF 22–24. Compare a 10-second sample before encoding the full file.
Check the result and keep the original
Open the compressed file and check text sharpness, face detail and audio sync. Lossy compression can't be undone, so archive the original before deleting anything. If an attachment is still too large, share a link (Drive, OneDrive, WeTransfer) instead.
04 — FAQ
Common questions
Is a free file compressor really free, with no hidden costs?
7-Zip, Squoosh, HandBrake and PDF24 are free with no limits or ads. TinyPNG is free for up to 20 images of 5 MB each per batch, and Pro removes those caps. Avoid 'free compressor' downloads from ad-heavy sites, which often bundle adware. Download only from the official sites.
Why doesn't zipping make my file smaller?
Formats such as JPG, MP4, MP3, PNG, DOCX and PDF are already compressed internally, so ZIP or 7z finds almost no redundancy left (about 0–3% savings). To shrink them, re-encode with a format-specific tool: Squoosh for images, HandBrake for video, PDF24 for PDFs.
Does compression reduce quality?
Lossless compression (ZIP, 7z, OxiPNG) restores files bit for bit. Lossy compression (WebP or AVIF quality settings, PDF image downsampling, video re-encoding) discards detail permanently. At sensible settings (WebP quality 75–80, video RF 22–24), most viewers can't see the difference.
How do I get a file under the 25 MB email attachment limit?
Gmail and Outlook cap attachments at about 20–25 MB, and Base64 encoding adds about 33% overhead. For PDFs, compress in PDF24 at 150 DPI. For videos, re-encode in HandBrake at 720p with H.265. For anything larger, send a Google Drive, OneDrive or WeTransfer link (WeTransfer's free plan allows up to 3 GB).
What are the best alternatives if I need advanced features?
WinRAR (about 30 USD, with an unlimited 'trial') adds recovery records for damaged archives. Zstandard (zstd, free) compresses and decompresses much faster than 7z at similar ratios, which suits backups and servers. For automated image pipelines, Sharp (Node.js) and libvips are free. ImageOptim (free, Mac) batch-optimizes images in place.
Scores reflect our own assessment of free-tier value. Prices and limits change, so check them on each provider's site before you buy.