What makes the best free file converter in 2026

There are hundreds of "free" file converters out there. Most of them aren't very good. Here's what to look for.

Privacy first A real converter does as much as possible in your browser. If a tool needs to upload your file, it should delete it immediately afterwards — and tell you when.

Speed Modern WebAssembly makes browser-side conversion almost as fast as desktop software. There's no reason to wait in a queue for simple jobs.

Output quality Sensible defaults. Lossless where possible. No watermarks. No ads injected into the file.

Why we built ConvertThoseFiles We wanted a converter we'd actually trust to handle work files. Every conversion runs entirely in your browser — your files are never uploaded to any server. No watermarks, ever.