Why a finished document still needs numbering
Numbers get added after the fact more often than you would expect. A document was assembled from several sources and each section restarted at one. A scan has no numbers at all. A pack of appendices from different authors needs a single continuous sequence so that a covering letter can refer to page forty and mean something.
The situation these have in common is that the source files are unavailable or too numerous to re-export. Stamping the assembled PDF is the practical answer, and done properly it costs nothing — the numbers are drawn into each page as text, so they stay selectable and searchable rather than becoming pictures.
Numbers are for referring to things
That is the whole purpose, and it settles most of the decisions. A page number exists so that two people looking at different copies can name the same page — in a meeting, in a citation, in an email saying the clause on page twelve needs revisiting.
Which means the number has to be unambiguous and it has to be findable. A single continuous sequence beats a clever one. If someone has to explain the numbering scheme before quoting a page, the scheme has failed.
Where to put them
Bottom centre is the safe default. It survives every binding, it is where readers look, and it is furthest from the content on most layouts.
Bottom outer corners — right on odd pages, left on even — is the book convention and is genuinely better for anything printed double-sided and bound, because the number lands where a thumb flicks. It only makes sense when you know the document will be printed that way.
The real constraint is what is already there. The [msm_tool slug="pdf-page-numbers"] draws over existing content rather than moving it, so a number placed where the document already has a footer will overlap it. Look at the busiest page before choosing a position, not the first one — the cover is usually clear and tells you nothing.
Front matter, and the skip
Covers, title pages and contents pages usually should not carry a number, and this is the most common adjustment. Skipping the first page or two means the sequence begins where the document proper begins.
Then a decision follows immediately: should the first numbered page be 1, or should it be 3 because two pages precede it? Both are defensible and they answer different questions. Starting at 1 gives a clean document numbering. Starting at 3 means the printed number matches the physical position, which is what anyone counting pages in a stack — or extracting a range later — will assume.
For anything that will be referenced, printed or split, matching the physical position causes less trouble. Formal front matter numbered in roman numerals is the traditional third answer, and it needs to be done in the source rather than stamped on afterwards.
Choosing a format
A bare number is right for most documents. "Page 4 of 40" is right where completeness matters — legal bundles, submissions, anything sent as a scan where a recipient needs to know nothing is missing. That format is the one worth using for documents that travel, precisely because it makes a missing page visible.
Where a total appears, remember that the tool counts from the pages it is numbering. If you skipped a cover, decide whether the total should include it, and check the last page says what you expect rather than assuming.
Size and contrast
Nine to eleven point is the usual range. Smaller vanishes on a photocopy, larger competes with the content.
Two things people forget. A number in mid-grey looks refined on screen and disappears in a third-generation photocopy, which is the state a legal bundle is usually in by the time anyone reads it. And on a scanned document, a number placed over a dark or noisy area of the image is effectively invisible — scans have no clean margins, only areas that happen to be pale.
Check the last page
Number, then open the result and look at three places: the first numbered page, to confirm the skip and the start value are right; a page in the middle with a busy footer, to confirm nothing collides; and the last page, to confirm the sequence ends where it should.
That last check catches the mistake that matters most — an off-by-one in the start value, which is invisible at the beginning and unmistakable at the end, and which turns every page reference in the covering letter into a small lie.