PDF Pages Have Different Sizes — How to Make All Pages the Same
A PDF where some pages are A4, some are letter, and others are unusual sizes causes printing and presentation problems. Here's how to normalize all pages to the same dimensions.
A PDF with mixed page sizes — some A4, some Letter, some custom dimensions — is usually a merged document where source files had different page sizes, or a presentation where slides were resized inconsistently. Mixed-size PDFs print incorrectly (some pages scale to fit, others are clipped) and look unprofessional in presentations. The fix is to normalize all pages to a single target size.
Identify Which Pages Are the Wrong Size
Use FixMyPDF Page Dimensions to check the size of every page in the document. This reports each page's width and height in points, millimetres, or inches. Note which pages are non-standard and what size they are — you need this information to decide the target size and the appropriate scaling strategy (scale-to-fit, crop, or pad).
Resize All Pages to One Standard Size
Use FixMyPDF Resize to set all pages to a uniform size: A4 (210 × 297 mm) for international documents, Letter (8.5 × 11 in) for US documents. The resize tool scales page content to fit the new dimensions. Choose "fit within" to scale without cropping (content may have white borders on some pages) or "fill and crop" to fill the new page size (edges of oversized content may be clipped). For a merged document where all content should be equally accessible, "fit within" with white padding is the safer choice.
Mixed Size After Merging Documents
When you merge PDFs, each source document's page dimensions are preserved — a merged Letter + A4 document will have alternating page sizes. Prevention: resize all source PDFs to the same dimensions before merging. If already merged: use Acrobat Pro's Print Production → Preflight → "Scale pages to specified size" fixup to scale all pages to a single target in one operation. The page content is scaled proportionally; margins adjust accordingly.
Crop Box vs Media Box: What Determines Page Size
PDFs have multiple "box" definitions: Media Box (the full physical page area), Crop Box (what's displayed and printed), Art Box, Bleed Box, Trim Box. The displayed page size is determined by the Crop Box (or Media Box if no Crop Box is set). Some PDFs appear as different sizes not because the Media Box differs but because different pages have different Crop Boxes set (clipping different amounts from the same-sized Media Box). In Acrobat Pro: Document Properties → Page Size shows the effective displayed size per page. Use Crop Pages (under Organize Pages) to set a uniform Crop Box across all pages if Media Box sizes are already equal.
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