Formats

everything it handles

Verified against the real engine, not written from memory. Where something does not work, it says so here rather than failing later.

Images and PDFs

From	PNG	JPEG	TIFF	GIF	BMP	HEIC	PDF	TXT
PNG · JPEG · TIFF · GIF · BMP · HEIC	●	●	●	●	●	●	●	●
WebP	●	●	●	●	●	●	●	●
PDF	●	●	●	●	●	●	–	●

A PDF of more than one page becomes a .zip of numbered images, because one image cannot hold a hundred pages. Suffix asks first, and names the result document.zip rather than the document.jpg you typed.

WebP goes in but not out. macOS ships a WebP decoder and no encoder, so renaming to .webp is refused outright rather than producing something broken.

Video and audio

From	MOV	MP4	M4V	M4A	WAV	AIFF	MP3
MOV · MP4 · M4V	●	●	●	●	●	●	○
M4A · WAV · AIFF · MP3	–	–	–	●	●	●	○

Video to video normally copies the existing streams instead of re-encoding, so it is fast and loses nothing. Video to audio extracts the soundtrack. Audio cannot become video.

○ MP3 needs a helper. macOS ships an MP3 decoder but no encoder, so suffix uses ffmpeg or lame when one is installed:

brew install ffmpeg

.m4a is the native equivalent and needs nothing.

Documents

From	To PDF
Pages · Keynote · Numbers	● exact — needs that Apple app installed
Word · RTF · OpenDocument · HTML · plain text	● approximate

Before you send it

Only iWork files convert exactly, because suffix asks Pages or Keynote to export them. Everything else is re-laid-out by macOS's own text engine: text and basic formatting survive, but tables, columns, headers and footers, and exact pagination do not. Suffix says so on the notice — check the result.

What it never touches

Archives, code, spreadsheets, other applications' libraries, and anything whose contents are not a format above. A .zip renamed to .png is left exactly as it is, and your Photos library is never opened — it is a database, not loose files, and writing into it would break it.