KOReader PDF settings that make documents readable
KOReader is the best PDF reader on most e-ink devices, but only once it is set up. Here is the difference between page mode and reflow, and the crop, zoom and contrast settings that matter.
Last updated September 2026
A PDF opened cold in any reader is usually disappointing: tiny text, huge white margins, a page that will not fit. KOReader gives you the tools to fix that, and they are worth learning because no stock reader matches them.
First decision: page mode or reflow
Tap the bottom of the screen for the document menu. The key control is the reading mode:
- Page mode shows the PDF exactly as laid out — one fixed page at a time. Use it for anything where layout carries meaning: academic papers, sheet music, comics, forms, illustrated books. You then use crop and zoom to make it readable.
- Reflow mode re-pours the text to fit the screen and lets you change font size like an EPUB. Use it only for PDFs that are essentially just text — a plain report, a novel exported to PDF. It mangles tables, footnotes, multi-column layouts and anything with figures.
Most document PDFs are read in page mode with the settings below. Reflow is a fallback.
Page mode: crop, zoom, columns
- Page crop. Trims the white border so the text fills more of the screen. Set it to “auto” and KOReader detects the margins; use “manual” to drag the crop box yourself on a page that fools the auto detector. On an A4 or US-Letter scan this alone enlarges the text 20–30% with no zooming.
- Zoom mode. “Fit content” works with the crop to fill the screen with the text block. “Fit width” is good for a single-column page you will scroll down. “Fit page” shows the whole page — only comfortable on a large screen.
- Columns. For a two-column paper, set the zoom to follow columns (“column mode” / “fit column”): a page turn moves down the left column, then to the right, then to the next page. This is the single biggest improvement for academic PDFs.
- Panning and page-turn behaviour. In multi-column or zoomed views, KOReader can auto-advance the view down and across a page on each tap. Set this once and the button turns just walk through the document.
Contrast for old scans
Scanned books are often grey. The document menu has a contrast / gamma control that darkens the ink. Push it far enough to be crisp, not so far that thin strokes break up. There is also a “sharpen” option that helps small type.
When the file is just too heavy
A 300 MB scanned book turns pages slowly no matter what. Options: lower the render quality while reading, set full-screen refresh to every few pages instead of every page, or re-process the file on a computer to a lower resolution. KOReader’s engine is faster than most, but physics still applies.
The short version
Page mode, auto crop, fit-content zoom, column mode for two-column papers, and a contrast bump for scans. Reflow only for PDFs that are nothing but text.