MOBI to PDF: Page Setup, Margins and Fonts That Print Well

You want to print one chapter for a book club, or email three pages to a friend who has never owned a Kindle. You double-click the .mobi file and… nothing useful happens. MOBI is Amazon's old ebook format, and outside Kindle apps and a handful of readers it's a dead end: no print dialog, no preview in Mail, no thumbnail in Google Drive.

The fix is a MOBI to PDF conversion. PDF opens on every phone, tablet, browser and printer on earth, and it keeps the page layout you choose instead of reflowing it. The catch is that a careless conversion gives you 400 pages of 9-point text squeezed into a 1-centimetre margin. This guide shows the settings that matter — page size, margins and fonts — plus the exact Calibre command and the one-minute online route.

Decide the target before you convert: paper or screen

A PDF has fixed pages, so you have to commit to a page shape up front. Pick one of these two profiles and the rest of the settings follow.

• Printing (A4 or US Letter). Generous outer margins so the text isn't eaten by the printer's unprintable edge or a binder clip. Body text around 12–13 pt. Expect a 300-page novel to land near 180–220 printed pages.
• Tablet or phone reading. A small custom page, roughly 150 × 200 mm, with tight 10–12 mm margins. Small pages mean the text fills the screen without pinch-zooming — the single biggest reason people say a converted PDF is unreadable on an iPad.

If you only need a chapter, convert the whole book anyway and print a page range from your PDF reader. It's faster than trying to slice the MOBI first.

The fast route: convert MOBI to PDF online

If this is a one-off — one book, one email to a friend — don't install anything. Upload the file to our MOBI to PDF converter, wait for the job to finish and download the result. A typical novel such as the-time-machine.mobi at 480 KB comes back as a PDF of roughly 1–2 MB, because the text gets laid out on fixed pages and the fonts are embedded.

Three things to check before you hit print:

• Open page 1 and page 50 — if the text touches the paper edge, redo it with a larger-margin setting or use Calibre below.
• Scroll to a chapter break. Headings should start a new page, not float mid-page.
• Look at any images or tables. Illustrated cookbooks and technical books suffer most from automatic reflow.

If you also have .azw3, .epub or .lit files lying around from the same era, the ebook converter hub covers those formats too.

The hands-on route: Calibre's ebook-convert

When you're converting a shelf of books, or you care about typography, use Calibre's command-line tool ebook-convert. It ships with the desktop app (on macOS it lives inside /Applications/calibre.app/Contents/MacOS/). The basic shape is input file, output file, then options.

ebook-convert "dracula.mobi" "dracula.pdf"

That works, and it looks mediocre. The options below are what turn it into something you'd actually hand to someone.

Page setup and margins for print

Calibre measures PDF margins in points: 72 pt = 1 inch = 25.4 mm. This is a solid A4 print recipe with a wider inner margin feel and room for a staple:

ebook-convert "dracula.mobi" "dracula-print.pdf" \
  --paper-size a4 \
  --pdf-page-margin-left 60 \
  --pdf-page-margin-right 60 \
  --pdf-page-margin-top 50 \
  --pdf-page-margin-bottom 55 \
  --pdf-default-font-size 13 \
  --pdf-page-numbers \
  --preserve-cover-aspect-ratio

Swap --paper-size a4 for letter in North America. --pdf-page-numbers is worth the two seconds: a stack of unnumbered loose pages is a disaster waiting to happen.

Page setup for a tablet

For an iPad or an Android tablet, build a small page instead of shrinking A4:

ebook-convert "dracula.mobi" "dracula-tablet.pdf" \
  --custom-size 150x200 --unit millimeter \
  --pdf-page-margin-left 28 \
  --pdf-page-margin-right 28 \
  --pdf-page-margin-top 28 \
  --pdf-page-margin-bottom 28 \
  --pdf-default-font-size 15

A larger base font on a smaller page is the trick — the same text that needs 13 pt on A4 wants 15–16 pt when the page is only 150 mm wide.

Fonts that survive the trip

MOBI files rarely carry their own fonts, so the converter picks defaults. Set them explicitly and embed them, otherwise the PDF may render differently on your friend's machine:

ebook-convert "dracula.mobi" "dracula-print.pdf" \
  --paper-size a4 \
  --pdf-serif-family "EB Garamond" \
  --pdf-sans-family "Source Sans Pro" \
  --pdf-mono-family "DejaVu Sans Mono" \
  --embed-all-fonts \
  --pdf-default-font-size 13

Use a serif for prose on paper (Garamond, Georgia, Charter) and a sans for screen reading. The family name must match a font installed on your system — if Calibre can't find it, it silently falls back, so check page 1 of the output.

Two extras that pay off on long books: --pdf-add-toc generates a clickable table of contents page, and --pdf-header-template / --pdf-footer-template let you put the book title in a running head. Batch a whole folder in one line:

for f in *.mobi; do ebook-convert "$f" "${f%.mobi}.pdf" --paper-size a4 --pdf-default-font-size 13; done

The one thing that will block you: DRM

If your file came from the Kindle Store and still carries DRM, no converter — ours, Calibre's, anyone's — will open it. You'll see an error about an unsupported or encrypted file. DRM-free MOBI files (Project Gutenberg, Humble Bundle, StoryBundle, author newsletters, your own exports) convert without complaint. If you're unsure, try the conversion: a clean PDF means the file was DRM-free all along.

Your 60-second recipe

• Sharing a few pages? Convert online, print the page range you need from the PDF viewer, done.
• Printing a whole book? A4 or Letter, 50–60 pt margins, 13 pt serif, page numbers on.
• Reading on a tablet? 150 × 200 mm custom page, ~28 pt margins, 15 pt font.
• Converting a shelf? The for f in *.mobi loop above, then spot-check three files.

Either way, the goal is the same: turn a file that only Kindle understands into one that every device, printer and inbox already does.

MOBI to PDF: frequently asked questions

Will the PDF keep my highlights and notes? No. Highlights live in Kindle's sidecar data, not in the MOBI file itself, so they don't travel. Export them from the Kindle app separately if you need them.

Can I read a MOBI file on an iPad without converting? Only inside the Kindle app, and only if you email or sync the file into your library first. A PDF opens in Files, Books, Safari and Mail with no setup — which is why converting is usually the shorter path.

Why is my PDF so much bigger than the MOBI? Fixed page layout plus embedded fonts. A 500 KB MOBI commonly becomes a 1.5–3 MB PDF. Drop --embed-all-fonts if size matters more than exact rendering.

How do I convert just one chapter? Convert the whole book, open the PDF, find the chapter's page range and print or export only those pages. Every PDF reader can do this; slicing the MOBI first cannot.

Is EPUB a better target than PDF? For reading on a phone, yes — EPUB reflows to the screen. For printing, emailing a fixed page or guaranteeing everyone sees the same layout, PDF wins.