A dark mode PDF reader — or a PDF that is already dark
You do not need to switch apps. Convert the file itself and it opens dark in whatever reader you already use.
No account required. Preview free, then £0.99 per document.
The app is not the problem
Most PDF readers either have no dark mode at all, or their dark mode just inverts everything on screen while you are looking at it — the file underneath is still white, so it flips back the moment you open it somewhere else, print it, or send it to someone. Switching readers to solve this only half works, and only in that one app.
What you get instead
A new PDF file, with the same pages, genuinely dark. You download it and keep it. It is not a viewer, a plugin or a browser extension, so there is nothing to install and nothing that only works in one place — it opens dark in Preview, Acrobat, iOS Files, Kindle apps, a browser tab, or any other PDF reader you already have.
Why this is more reliable than an app setting
A reader's built-in dark mode is applied every time you open the file and can vary between apps and versions. Once the file itself is converted, there is no setting to find, no toggle that resets, and no difference between readers — the dark version is just what the file is now.
Questions
Do I need to install a new PDF reader?
No. You get back a regular PDF file that is already dark, so it works in whatever reader you already have installed.
What if my reader's own dark mode already works okay?
A reader's dark mode only applies inside that app, and many invert photographs into negatives. A converted file looks the same everywhere and keeps photographs intact.
Will it work on my phone as well as my computer?
Yes. It is an ordinary PDF file, so it works anywhere PDFs work — phone, tablet, computer or e-reader.
Can I still search and select text in the reader?
Yes, for almost every document. The colour instructions are rewritten rather than the pages being turned into images, so text stays selectable and searchable.