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Why was my A0 floor plan PDF page refused when I tried to convert it at 300 DPI?

Drop to 96 DPI, or switch to Zoom factor and enter 1.75, and the page goes through. At 300 DPI an A0 page needs a 9934 × 14042 px image, and the browser budget is 8000 px per side and 25 million pixels per page.

Published · 3 min read

The arithmetic that refused your page

An A0 page in a PDF measures 2384 × 3370 points, and an inch is 72 points. The DPI decides how many pixels each inch gets, so the page size is multiplied by the DPI divided by 72. These are the results of the same check the tool runs before drawing anything:

  • 300 DPI: 9934 × 14042 px. A side is longer than 8000, so it is refused.
  • 200 DPI: 6623 × 9362 px. The long side is still over 8000, refused.
  • 150 DPI: 4967 × 7021 px. Both sides fit, but the total is about 34.87 million pixels, over the 25 million budget, so it is refused too.
  • 96 DPI: 3179 × 4494 px, about 14.29 million pixels. It fits.

There are two separate tests: side length and total pixels. A very wide page can fail the first, while a page that is big in every direction can fail the second even when each side is acceptable.

Why it refuses instead of trying

While a page is being drawn it needs 4 bytes per pixel, so 25 million pixels is roughly 100 MB for a single page. Going past that can crash the browser tab or silently produce a truncated image. So every page is checked up front, and if any is too large you get a message with how many pages were refused and the two limits, and nothing is rendered. In the size list, the refused group is highlighted as a warning, so you know before pressing anything.

Finding the highest setting that fits

The DPI menu in PDF to images offers fixed steps: 72, 96, 150, 200 and 300. For an A0 sheet the jump from 96 to 150 is huge, and that is where the zoom factor helps, because it accepts any value from 0.1 to 6.

  1. Switch from DPI to Zoom factor.
  2. Enter 1.75. The plan shows 4172 × 5898 px, about 24.61 million pixels, just under the limit. That is the same as 126 DPI.
  3. Try 1.8 if you like: it becomes 4292 × 6066 px, about 26.04 million, and the warning comes back.
  4. Settle on the last value with no warning, then press Convert.

If that still is not enough detail

A whole floor plan 4172 px wide is fine for viewing and sending, but it will not show the tiniest figures in a dimension table as sharply as a print would. The tool does not tile one page into several images, so if you need finer detail, ask the architect's office for an export of just the part you care about, or open the original drawing in the program that produced it.

Common questions

Does the limit depend on my computer?

No. The tool uses a fixed, tested budget of 8000 px per side and 25 million pixels, chosen so that an ordinary machine copes.

My file mixes one A0 sheet with A4 pages. Is everything refused?

If any selected page is over the limit, the conversion does not start. Leave the A0 page out of the Pages field, convert the rest at your usual DPI, then convert the A0 page alone with a smaller zoom.

Does 72 DPI give the page at its real size?

It gives one pixel per point, 2384 × 3370 px for A0. That is sharper than most screens but less detailed than a zoom of 1.75.