Altarsoft PDF Reader has been discontinued. Similar apps include SumatraPDF, which is free and open source. Other options are Okular, Foxit PDF Reader, Evince and MuPDF. PDF Readers like Altarsoft PDF Reader are a crowded field, with more than 50 alternatives for Windows, Mac, Linux, Android and iPhone.
Zathura is a highly customizable and functional document viewer. It provides a minimalistic and space saving interface as well as an easy usage that mainly focuses on keyboard interaction.
Germany
EU
Besides exceptionally fast launching and displaying speed, Gaaiho Reader is reliable in printing, filling forms annotating documents and adding bookmarks.
Taiwan
In version 8, Google Chrome introduced a free PDF viewer, installed by default. While this plug-in lacks many features of the Adobe Acrobat Plug-in, it is much faster and lighter, and updates with the browser rather than an external utility.
United States
Ashampoo PDF Free is a software for opening, reading, and creating PDF files. It includes a built-in printer driver for generating PDFs from any Windows application, a compact and fast PDF reader, and the ability to fill out interactive and static forms.
GermanyEU
A simple PDF document viewer, in the lines of Evince but without using the Gnome libraries. ePDFView is a free lightweight PDF document viewer using Poppler and GTK+ libraries.
Malaysia
Panels is a CBR/CBZ/PDF comic reader for your iPhone and iPad devices. Enjoy reading your comics in a clean and delightful interface.
SpainEU
The simplest PDF viewer. Safe (doesn't require permissions), lightweight (just 6,9MB) and modern.
ItalyEU
AI powered productivity tool for reading, understanding and taking notes on PDFs and long websites. Users can search, summarise, extract and define keywords, ask google-search type questions and be taken straight to the answers.
United Kingdom
Xpdf is a free PDF viewer and toolkit, including a text extractor, image converter, HTML converter, and more. Most of the tools are available as open source.
United States
Cloud-based PDF viewer and annotation tool for your browser. Perfect for Chromebook 1:1 schools. View, export, print and share your PDF files straight from your browser. Kami works on all browsers and works best with Google Chrome.
New Zealand