SumatraPDF reader supports the following document types:
  • PDF (.pdf, .ai)
  • eBook formats:
    • unencrypted EPUB (.epub)
    • MOBI / Kindle (.mobi, and un-encrypted .azw, .azw3, .azw4, .prc)
    • FictionBook (.fb2, .fb2z, .fbz, .zfb2, .fb2.zip)
    • Palm DOC (.pdb)
    • plain text (.txt, .log, .nfo, .tcr, …)
  • Markdown (.md, .markdown), rendered as GitHub Flavored Markdown
  • comic book files: .cbz, .cbr, .cbt, .cb7 (and .ora)
  • archive files (.zip, .rar, .7z, .tar) containing images
  • DjVu (.djvu, .djv)
  • Microsoft Compiled HTML Help (.chm)
  • XPS (.xps, .oxps, .xod, .dwfx)
  • SVG (.svg)
  • images:
    • PNG (.png)
    • JPEG (.jpg, .jpeg, .jfif)
    • GIF (.gif), including animations
    • TIFF (.tif, .tiff), including multi-page
    • BMP (.bmp, .dib)
    • TGA (.tga)
    • WebP (.webp)
    • JPEG XR (.jxr, .hdp, .wdp)
    • JPEG 2000 (.jp2, .j2k, .jpx, .jpf, .jpm, .j2c)
    • AVIF (.avif)
    • JPEG XL (.jxl)
    • HEIF / HEIC (.heic, .heif) — built-in decoder; see below
If Ghostscript is installed, we support PostScript (.ps, .eps) and PJL (Printer Job Language) files.

HEIF / HEIC support #

SumatraPDF can open HEIF images (.heic, .heif) and AVIF (.avif) with a built-in decoder:
  • HEIC (typical phone stills, HEVC-coded): decoded in-process; no Windows codec required for most files
  • AVIF (AV1-coded): decoded in-process via dav1d
  • Grids, overlays, and common transforms (crop / rotate / mirror) are handled for still images
If built-in decode fails, on Windows we still try the system WIC path (for example if a third-party HEIF codec is installed). That fallback is optional for typical HEIC/AVIF files.
You can make SumatraPDF the default program for handling those file types.