How to read PDFs comfortably on a tablet, phone or e-reader

Most PDFs are designed for a sheet of A4 or Letter paper. On a tablet or e-reader the whole page is squeezed onto a smaller screen, the text becomes tiny, and a lot of the screen is spent on white margins. A few adjustments to the file make a large difference.

Why PDFs read badly on small screens

Unlike a web page or an e-book, a PDF has a fixed layout: every line sits at an exact position on the page. A reader can zoom, but cannot reflow the text to fit the screen. So the useful question is how much of the screen the text actually fills — and on a typical document, margins take up a surprising share.

Crop the margins

Trimming the white border is the single most effective change. Removing a 20 mm border from an A4 page makes the text roughly a third larger on the same screen.

1. Add the PDF to Crop PDF Margins. The first page appears with a dashed outline.
2. Drag the margin slider until the outline sits just outside the text. Everything inside the outline is kept.
3. Untick the equal-margins option if one side is wider, as with documents that have a binding margin.
4. Crop and download, then copy the new file to your tablet.

Cropping hides the margins rather than deleting them, so text stays sharp and selectable and the file size barely changes. Leave a few millimetres of margin; text that touches the screen edge is tiring to read. If page numbers or headers sit in the margins, decide whether you need them before cropping them off.

Pages that differ

A cover or title page often has different margins from the body. Crop only the main pages by entering a page range, such as 3-120, and leave the rest alone.

Reading at night

A bright white page in a dark room is uncomfortable. Many reading apps have a night mode, but it belongs to the app: open the same file elsewhere and you are back to white. Invert PDF Colours turns the file itself into light text on a dark page, so it looks the same in every app.

• It suits text documents, papers and slides with plain backgrounds.
• Photographs come out like film negatives, so it is a poor fit for picture-heavy documents.
• The inverted pages are re-drawn as pictures, so their text can no longer be selected — keep the original for searching and quoting.

Two-column academic papers

Two narrow columns on a portrait page are the hardest layout on a small screen. Some approaches that help:

• Crop the margins first, then read in landscape, zoomed to one column's width.
• Use your reader's column or “fit width” zoom, if it has one, and scroll down each column.
• On a large tablet, portrait with cropped margins is often readable without zooming.

E-readers

E-ink readers have smaller screens than most tablets and refresh slowly when you zoom, so cropping matters even more. Some e-readers and their companion apps can convert a PDF into a reflowable format; this can work well for plain text but often scrambles tables, figures and equations. A cropped PDF keeps the layout intact, which is the safer choice for anything technical.

Printing a document you have cropped

Most printers honour the crop, so only the visible area prints, possibly enlarged to fill the paper. To print the original page with its margins, use the original file. If you need a document on a different paper size for printing, the PDF Page Size Converter scales it properly.