pdf tool

Remove blank pages from a PDF

To remove blank pages from a PDF, drop the file: every page is measured for ink, and pages under the threshold you set are flagged in red with their figure shown. Check the flagged pages, overrule any you want to keep, and save the file without them.

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How it works

  1. 1

    Drop the PDF

    Each page is drawn small and measured, and its ink figure appears under its thumbnail as the pages load.

  2. 2

    Set the threshold

    A page counts as blank when its ink is under the figure on the slider, 0.30% to start. Leave the outer 6% ignored for scans, so scanner shadows and punched holes do not count as ink.

  3. 3

    Check the red pages

    Flagged pages are crossed out in red. Tap any page to overrule the verdict: keep a flagged page, or remove one the tool kept.

  4. 4

    Save

    The file is saved without the red pages, and bookmarks and form fields on the remaining pages are kept. Nothing is uploaded and nothing is stored, ever.

How a page is judged blank

Each page is rendered at 400 pixels on its long side and turned into brightness values. The tool first finds the paper colour, the brightness that half the page sits at or above, so a grey scan of a white sheet is judged against its own grey rather than pure white. A pixel counts as ink when it is clearly darker than that paper. The page's ink figure is the share of pixels that are ink, and a page under the threshold is flagged for removal.

Where blank pages come from

Most come from duplex scanning. A scanner set to read both sides captures the empty back of every single sided sheet, so a 20 page letter becomes 40 pages, half of them blank. Others come from word processors that add an empty page after a section break, and from printing to PDF with a separator sheet. Taking them out before you send or sign a file makes it shorter to read and easier to initial page by page.

Choosing the threshold

Start at 0.30% and read the figures under the thumbnails. In testing, an empty page measured 0.00%, a page with only a small page number 0.01%, a page of body text 3 to 6%, and a scanned letter 10 to 12%. Put the slider between the highest page you want gone and the lowest page you want kept; it moves in steps of 0.01%. Ignoring the outer edge helps with scans, because the dark band a scanner lid leaves along one side can otherwise outweigh a faint page number.

Limits worth knowing

A threshold is a blunt rule. A page with only a faint logo, a pale watermark or one light signature line can read as blank when the slider is high, which is why every flagged page is shown before anything is removed and one tap keeps it. A page that is mostly a dark design is never treated as blank. The measurement is made on a small render, so a lone dot or a very fine hairline may not register. A PDF needs at least one page, so the tool will not save a file in which every page is flagged.

What the saved file keeps

The blank pages are taken out of the original file rather than the other pages being copied into a new one. Bookmarks that point to pages that stay still work, and form fields on those pages keep their values. Bookmarks that pointed at a removed page are unlinked, and the removed pages' content leaves the file instead of lingering hidden inside it.

Limits

  • A page with only a faint logo, a light signature line or a page number can read as blank at a high threshold. The preview is there to check, and one tap keeps a page.
  • Ink is measured on a small render of each page, so a single tiny mark may fall under the threshold.
  • A page that is mostly a dark design is never treated as blank.
  • At least one page must stay. When every page reads as blank, the tool says so and will not save.

What it does not do

  • It does not clean specks, shadows or punched holes off the pages it keeps.
  • It does not spot pages that only repeat a heading, such as an empty form page with its title.
  • It does not open password protected PDFs.

Questions people ask

Will it remove a page that has only a page number on it?

Usually, yes. A small page number on an otherwise empty page measures about a hundredth of a percent, close to a truly empty page and well under the starting threshold, so it is flagged with the blank pages. If such pages must stay, for example to keep the numbering, tap each one to keep it. Your choice holds when you move the slider.

Does it work on a scan made with a phone?

Yes, as long as the scan is saved as a PDF. Phone scans often have a grey or uneven background, which is why each page is judged against its own paper colour rather than pure white. Keep the outer 6% ignored, since phone scans often catch a strip of the table or a shadow along one edge.

Can I remove blank pages from several PDFs at once?

One file at a time. To clean a batch, merge the files into one PDF with the merge tool, remove the blank pages here, then split the result back into parts if you need separate files. That way the threshold you settle on applies to every page in the same way.

Will the pages that stay lose quality?

No. The pages that stay are not re-rendered or compressed; the blank pages are taken out of the original file and it is saved again. The small thumbnails are only used to measure the ink and to show you the pages, and they never go into the saved PDF.

Why was a page with writing on it flagged?

Its ink measured under the threshold, which happens with pale pencil, light blue ink, a faint stamp or very small text. Read its ink figure, then lower the slider until the page turns white again, or tap it to keep it whatever the slider says. A page you tap keeps your choice when you move the slider later.

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Written and checked by the OneCraft team. Last checked .