
Sumatra PDF
Evince
calibre
MuPDF
Adobe Reader
FBReader
PDF-XChange Editor
Okular is a universal document viewer based developed by KDE.

OCR Text Detection Tool
Free Easy OCR
Onlineocr.net
DeepSeek OCR App
Easy Screen OCR
OCR.space
Intelligent OCR
Easily convert images, scanned documents, and low-quality photos to text with our online OCR tool. Fast and accurate text extraction.
Which is more popular?
Based on our record, Okular seems to be more popular. It has been mentioned 44 times since March 2021.
Website, pricing, platforms and company facts side by side.
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| Website | okular.kde.org | ocr.ac |
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| Listed in |
What each product offers, as listed by its team.


Possible disadvantages
An editorial look at what each product does well and who it suits.


Overall verdict
Why this product is good
Recommended for
Okular is recommended for students, educators, professionals, and any users who require a reliable and feature-rich document viewer capable of handling a wide range of file formats. It is particularly beneficial for those who value open-source software and need robust annotation and document management tools across different platforms.
Overall verdict
Why this product is good
Recommended for
Walkthroughs and reviews on video.
okular, program for annotating your books in linux
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How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing Okular and OCR.ac.
OCR.ac's answer:
OCR.ac provides powerful and free tools, OCR is not cheap and its a free tools platform.
OCR.ac's answer:
User should choose OCR.ac because its free and its results are as good as other competitors and competitors are charging too much, so, the best choice is OCR.ac.
OCR.ac's answer:
OCR.ac provides OCR based tools, which is the need of almost all type of audience, like teachers, students, researchers, data entry persons, businesses with tons of paperwork, etc.
Share your experience with using Okular and OCR.ac. For example, how are they different and which one is better?
External articles and on-site reviews we used to compare the two products.


Verdict: Okular is an open source and can be used free, which is probably its main advantage. At the same time, its basic functionality is meant to be not only highly competitive with PDF Expert but rather overcomes...
Okular is another open-source and cross-platform document viewer developed by KDE and is shipped as part of the KDE Application release.
We have no reviews of OCR.ac yet. Be the first one to post
Recommendations tracked on public social media and blogs since March 2021.


If you mean signing as in "signing with your handwritten signature", you could use Okular () which easily allows you to do that. Filling out forms also works nicely. Source: almost 3 years ago
I was in a similar position lately until I found Okular. Have you tried it? https://okular.kde.org/. - Source: Hacker News / about 3 years ago
I would try Okular first, though, which is free and open source: https://okular.kde.org/. Source: over 3 years ago
Tracking OCR.ac since Jul 2025.
When comparing Okular and OCR.ac, you can also consider the following products.

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Download this app from Microsoft Store for Windows 10, Windows 10 Mobile, Windows 10 Team (Surface Hub), HoloLens. See screenshots, read the latest customer reviews, and compare ratings for OCR Text Detection Tool.
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Evince is a document viewer for multiple document formats: PDF, Postscript, djvu, tiff, dvi, XPS...
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Sometimes we need to get the text out of photos or scanned documents for further editing and use.
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Free Online OCR service allows you to convert PDF document to MS Word file, scanned images to editable text formats and extract text from JPEG/TIFF/BMP files
Compare Onlineocr.net to Okular or OCR.ac: