Word to PDF Changed Your Fonts: Why Calibri Becomes Carlito

Your PDF opens, the layout holds, the page count matches. Then you check the document properties and the font is listed as Carlito. You never installed Carlito. You wrote the thing in Calibri.

Nothing is broken. That swap was deliberate, and the reason your pages didn't move is the same reason the name changed.

The version people actually complain about looks different: text reflows, a two page memo turns into three, a heading wraps one word early. That happens as well, but only with certain fonts, and which ones is entirely predictable.

I read the font list off the machine that runs our own Word to PDF conversions and checked what it does with every font people commonly use in Word. Below is the real substitution table, why five of those swaps are invisible and the rest aren't, and what to do when the typeface isn't up for negotiation.

Why Word to PDF changes fonts in the first place

A PDF page isn't a picture of your document. Text is stored as characters plus a reference to a font, and something has to supply that font: either it travels inside the file, or the program doing the rendering has a copy installed.

Our conversion is one command. LibreOffice 7.1.8.1 in headless mode, its Writer PDF export filter, one file at a time with a two minute ceiling:

soffice --headless --convert-to pdf:writer_pdf_Export --outdir /path/out yourfile.docx

That machine has 50 font families installed. Calibri is not one of them. Neither is Aptos, Arial, Georgia, Verdana, Tahoma, Segoe UI or Consolas.

This isn't an oversight. Those faces are licensed products, and Microsoft's own typography pages send organisations to a commercial licence for server installations. Every converter running on Linux has the same gap, whatever its marketing page says. When one claims it preserves your fonts because it has them all installed, the interesting question is which ones, and under what licence.

So the renderer asks the system for the nearest thing it has. That answer is not random, and you can look it up.

The substitution table our converter actually uses

One row per font, straight from the conversion server:

That last column has nothing to do with how alike the letters look.

Metric compatible is the entire trick

Carlito exists because Google hit this problem while shipping ChromeOS. It is drawn so each glyph occupies exactly the same width as the matching glyph in Calibri, and it's released under the SIL Open Font License 1.1. Caladea does the same job for Cambria.

Red Hat got there earlier. The Liberation family, first released on 9 May 2007, states metric compatibility with Arial, Times New Roman and Courier New as its aim, and every character matches the Monotype original in width and height.

Which is why the top five rows are safe. The shapes changed. The measurements didn't. Every line breaks at the same word, every paragraph fills the same number of lines, and a 12 page report stays 12 pages.

At body sizes most people won't notice Carlito standing in for Calibri unless the two sit side by side. Set a heading at 28pt and you will. That's the honest version, and it's a good trade against the alternative.

The fonts that genuinely move your text

DejaVu Sans is a perfectly good typeface and it is nothing like Verdana's width. Swap one for the other across a document and text reflows: lines take more or fewer words, paragraphs gain a line, page breaks slide down, a table column stops fitting. Georgia landing on DejaVu Serif does the same, so does Segoe UI landing on Cantarell.

My favourite entry in that table is Comic Sans MS, which resolves to Z003 Medium Italic. Z003 is URW's chancery face: a slanted calligraphic script. A birthday flyer comes back looking like a wedding invitation. Largest personality gap in the whole list, and nobody sees it coming.

Symbol fonts want checking by eye before you send anything. Symbol resolves to Standard Symbols PS, which is a fair match. Wingdings resolves to DejaVu Sans, a text font that was never built to carry those glyphs, so tick boxes and arrows are exactly the sort of thing worth opening the PDF to confirm.

Aptos is the version of this problem about to get common

Microsoft replaced Calibri with Aptos as the Office default. Steve Matteson drew it, the copyright line reads 2023, and it ships in six weights from Light to Black plus Display, Narrow, Mono and Serif variants.

There is no Carlito for Aptos. Calibri earned a metric compatible twin by sitting still for 15 years while the open source world caught up. Aptos is new, nothing matches its metrics yet, and our server falls back to DejaVu Sans. Your text reflows.

Two consequences. Documents created in the last couple of years are set in Aptos whether anyone chose it or not, so a template that used to convert cleanly may quietly stop. And Aptos is delivered as a cloud font through Office, so a colleague on an older build may not have it either. If your text moved and you don't know why, open the font box in Word and read what it actually says before blaming the converter.

How to see which fonts your PDF really contains

Stop judging by eye. Two ways to get the list.

In Acrobat Reader, open File, then Document Properties, then the Fonts tab. You get every font the file references, and anything marked Embedded or Embedded Subset travels with the document.

On a command line, pdffonts yourfile.pdf from poppler-utils prints a table: font name, type, then columns for embedded, subset and unicode. It's the fastest check I know.

Read two things out of that output. Carlito appearing where you wrote Calibri tells you substitution happened and exactly where. An embedded column reading no tells you the file depends on whatever the reader can find locally, which is how a document ends up looking different on every machine that opens it. LibreOffice does embed the fonts it used when exporting; the standard exception is the 14 base PostScript fonts, which every reader already carries.

Embedding fonts in Word before you convert

Highest hit rate of any fix here, and it comes with two traps.

In Word: File, Options, Save, then switch on Embed fonts in the file. LibreOffice has read fonts embedded in a .docx since 2013 and checks each font's own licence flags before using it, so an embedded font that permits the use gets used instead of a substitute.

Trap one is the checkbox directly underneath, Embed only the characters used in the document. Microsoft documents the behaviour plainly: use 32 or fewer characters of a font and Word embeds only those characters. Fine for a wordmark. Awful the moment someone edits the file and types a letter that wasn't in the original set.

Trap two is that not every font permits embedding at all. Font files carry a permission flag running from non-embeddable through preview and print, editable, and installable. Word skips the ones that refuse, and it doesn't make a fuss about it.

So verify instead of hoping. A .docx is a ZIP archive: copy it, rename the copy to .zip, open it, and look for a word/fonts folder holding files like font1.odttf. No folder means nothing was embedded. Those .odttf parts are ordinary OpenType files with the first 32 bytes scrambled against a GUID stored in fontTable.xml, which is a speed bump against casual reuse rather than encryption.

When the typeface isn't negotiable

Choose by what you're actually protecting.

• Pagination, not exact letterforms: you already have it. Stay on Calibri, Cambria, Arial, Times New Roman or Courier New and the metric compatible set holds your page count for you.
• A brand face in a template you control: move the template onto the substitute. House style set in Carlito means what you see locally is what everyone downstream receives, and the round trip stops mattering.
• A one-off document with Word already open: export from Word itself. It embeds from your own machine's fonts and no server is involved.
• Anything that must pass through a converter: embed first, run the ZIP check, then convert.
• Logos, wordmarks, decorative headings: make them images. Live text in a display font is the most likely thing to arrive wrong and it buys you nothing.

If someone handed you a PDF whose fonts already came out wrong and the original .docx is gone, you can convert the PDF back into an editable Word file, reset the fonts there and redo the export. Budget some time for fixing spacing by hand, because backwards out of a PDF is always the lossier direction.

The Word to PDF font check that takes 30 seconds

1. Open the .docx and read what the body font really is. Aptos, Segoe UI, Georgia, Verdana and Tahoma are the ones that will move your text.
2. If it's Calibri, Cambria, Arial, Times New Roman or Courier New, convert and stop thinking about pagination.
3. If it isn't, either change the font or turn on embedding under File, Options, Save.
4. Confirm the embed took by renaming a copy to .zip and looking for word/fonts.
5. Convert, then run pdffonts on the result or open the Fonts tab in Acrobat.
6. Compare the page count with the original.

Step six is the one to keep. Page count is a faster signal than rereading the document, because reflow always shows up there first.