Use a bounded page range
Choose a range such as 1-10 to limit the final PDF. The engine first converts the complete source, then selects pages, so a range does not remove the full-document conversion memory requirement.
Local processing uses local resources
The browser must decode the source and hold an intermediate PDF. A small compressed source can contain large raster images. Use a smaller source document when memory is limited; selecting fewer output pages alone may not be enough.
Join only reviewed outputs
If you convert a document in sections, confirm each section’s page count and order before combining the PDFs. Keep the range settings with the resulting filenames.
Plan around the complete source
Consider a 120-page source containing large scanned images. Selecting 1-3 produces a three-page final PDF, but the engine still converts the complete source before selecting those pages. That behavior works around a known page-selection issue in the pinned engine. Do not interpret the range as an instruction to read only three pages into memory.
A source is rejected above 50 MiB or 200 pages, and the worker also has a two-minute limit. These are limits rather than a promise that every document below them will finish. Highly compressed images, complex paths and unusual fonts can require considerably more memory than the source file size suggests, especially on a phone.
If the worker times out, first try a smaller source document exported from the original application. Closing other heavy browser tabs may also help a constrained device. Selecting fewer output pages alone may not solve the problem because the expensive full-source conversion remains. Cancel the current job before starting another and keep the source file unchanged.
For a document already split into sections, convert each section and record its original page interval in the filename. Check overlaps and missing pages before joining the PDFs. A sequence such as section-001-040 followed by section-041-080 is easier to audit than several files named output. Confirm that the combined order matches the original table of contents.