PDF24 is a generous free German PDF suite with a huge tool list and a Windows desktop app, but the web UI is dated and ad-supported.
| Feature | PDF Studio | PDF24 |
|---|---|---|
| Price | Free, no ads | Free, ad-supported |
| Signup required | No | No |
| Interface | Modern, mobile-first | Functional but dated |
| Target-size compression | Yes - 100KB/200KB/500KB/1MB presets | Quality slider only |
| OCR support | Yes, 100+ languages | Yes, fewer languages |
| ID card to A4 PDF | Yes, print-ready A4 | No dedicated tool |
| Files auto-delete | Yes, after 1 hour | Yes |
PDF24 is a solid free workhorse, especially on Windows. PDF Studio matches it on price while adding a cleaner mobile experience, exact target-size compression, and broader OCR.