The detail
Page length depends on spacing, font, and margins, but the common convention is about 500 words per single-spaced page and 250 words per double-spaced page. At roughly 1.33 tokens per word that is about 650 and 330 tokens respectively.
This is the most useful unit for deciding whether a document fits a model. A 200,000-token context window holds on the order of 300 single-spaced pages of prose — but remember the model’s answer and your instructions draw from the same budget.
PDFs and exported documents often carry hidden characters, headers, footers, and footnotes that add tokens beyond the visible body text. Import the file into the analyzer to count what the model will actually receive.