A document looks fine on screen, then the printout has its right edge missing, or the whole page is slightly smaller than expected, or a website refuses the upload. In most of these cases the page size of the PDF does not match the paper or the rule on the other side. This guide explains where the two sizes come from, what printers do when they disagree, and how to fix the file.
Two paper systems, two shapes
Most of the world uses the ISO 216 A series. The standard covers trimmed sizes of writing paper in the A and B series. In the A series every sheet has a height-to-width ratio of the square root of two, A0 has an area of one square metre, and cutting a sheet in half across its longer side gives the next size. A4 measures 210 × 297 mm.
The United States and Canada, and in part Mexico, still use North American sizes. Letter measures 216 × 279 mm (8.5 × 11 in) and Legal measures 216 × 356 mm (8.5 × 14 in). Other countries may use both systems side by side. Which size an office in a given country expects is best checked with that office.
What the difference does to a printout
Compare the numbers. Letter is 6 mm wider than A4 and 18 mm shorter. That is why the same file behaves differently on the two kinds of paper:
- Letter file on A4 paper: the page is 6 mm too wide. Printed at actual size, the sides are cut off. Printed with a fit option, the page is shrunk slightly and a strip of paper is left empty at the bottom.
- A4 file on Letter paper: the page is 18 mm too tall. Printed at actual size, the bottom of the page is cut off. Printed with a fit option, the page is shrunk and side margins grow.
- Many printers also cannot print to the very edge of a sheet, so text close to the edge of a page can be lost even when the sizes match.
What happens is decided by the print dialog, not by the PDF. Print dialogs usually offer a few scaling choices. Fit reduces or enlarges each page to the printable area of the selected paper. Actual size prints without scaling, and anything that does not fit is cropped. A custom percentage is also common. Some programs add a choice that shrinks only pages that are too large. Microsoft Edge shows the idea under Scale to print: Fit to printable area, Actual size and Custom. Edge also keeps the paper size in a separate setting under More settings, where Letter, Legal and A4 are listed. Other programs use different names for the same choices.
So a cut-off print usually means one of two things. Either the dialog was set to Actual size, or the paper size in the dialog does not match the paper in the tray.
Quick fix in the print dialog
- Set the paper size in the dialog to the paper that is really in the printer.
- Set page scaling to Fit, or Fit to printable area, or Shrink oversized pages.
- Check the preview. If the content still touches the edge, add a margin to the file as described below.
- Do not use Actual size unless the print must be true to scale, such as a drawing or a photo print.
This works when you control the printer. It does not help when a print shop prints your file as it is, when you want to hand the file to someone else, or when an upload form checks the page size.
When a portal cares about page size
Many portals only check the file type and the size in megabytes. Some also say which paper size to scan. The Income Tax Department of India, in its guidance on scanning documents for its e-filing portal, says: "Scan the document in A4 or Letter size only." It also says to scan at 300 dpi and to scan to a PDF. This shows two things. Some portals name the sizes they accept, and some accept both A4 and Letter. Read the upload instructions of the portal in question. If a notice lists A4 only, make the file A4 before you upload it.
At the time of writing (October 2026) that notice also says the department proposes to impose file size limits. Portals change these rules, so check the current page before you upload.
Resize the PDF itself with DocPro
Resizing puts every page of the file on a sheet of the size you choose. Pages are scaled to fit and centred, keeping their proportions. DocPro does this in the browser, so the file is not uploaded.
- Open Resize PDF. For the two common cases use Resize PDF to A4 or Resize PDF to Letter, which pre-select the size.
- Choose the PDF. The panel shows the current size of page 1 in millimetres, with a name such as Letter or A4 when it matches, and the page count.
- In Page size pick A4, Letter, Legal, A3, A5 or Custom size. For a custom size choose mm or in and enter Width and Height.
- Under Orientation, leave Match each page to keep wide pages landscape and tall pages portrait. Choose Portrait or Landscape to force one orientation.
- Set Margin (mm) if the printer clips the edges. A margin of 5 to 10 mm leaves a safe border. The margin must leave room for the page, or the tool asks for a smaller one.
- Tick Never enlarge pages, only shrink them to fit if small pages should stay small instead of growing to fill the sheet.
- Press Resize PDF and download the new file. The original is not changed.
Text and drawings stay sharp because each page is placed as vector content. Scanned pages stay at the resolution of the scan.
Fit, not stretch
Resize PDF has one way of working: scale to fit and centre. There is no stretch mode, because stretching would distort text and photos. When the new sheet has a different shape from the old page, empty space remains on two sides. Going from Letter to A4 leaves a strip at the bottom and top, and going from A4 to Letter leaves strips at the sides. Content is not re-flowed, so text does not wrap differently.
Related tools
- Crop PDF trims white margins with Auto-detect margins or by Top, Right, Bottom and Left values in points. It removes space around the content. It does not change the paper size, unless Also shrink the page size (MediaBox) is ticked. Use it before Resize PDF when a scan has wide borders, so the content can be scaled larger.
- Images to PDF has a Page size choice of Fit image, A4 or Letter. Its Orientation choices are Auto, Portrait and Landscape, and Margin runs from 0 to 40 mm. Pick A4 or Letter when phone photos of a document must become a standard page.
- Compress PDF is the next step when the page size is right but the upload limit is not.
What DocPro cannot do here
- Links and form fields are not carried over to resized pages. If the form must stay fillable, fill it first or resize only a copy that is meant for printing.
- Resizing does not redraw the layout. A page designed for Letter will have uneven margins on A4. If the layout matters, change the page size in the program that made the document and export again.
- It does not repair a print dialog set to Actual size. Resizing helps most when the file itself must match the paper.
- It does not make a portal accept a file. If a portal asks for a different resolution, file size or format, the file must meet those rules too.
Rules differ by office and change over time. For a high-stakes document, ask the receiving organisation which size it expects.
Frequently asked questions
Why does my PDF print with the edges cut off?
The most common cause is a print dialog set to Actual size, which prints without scaling and crops what does not fit. Choose Fit, Fit to printable area or Shrink oversized pages, and check that the paper size in the dialog matches the paper in the printer.
Is US Letter bigger or smaller than A4?
Neither. Letter (216 × 279 mm) is 6 mm wider and 18 mm shorter than A4 (210 × 297 mm), so a file for one does not fit the other exactly.
Do I have to convert a Letter PDF to A4 before uploading it to a portal?
Only if the portal says so. Some portals accept both. India's Income Tax e-filing guidance, for example, says to scan in A4 or Letter size. Read the upload instructions and convert only when they name a size you do not have.
Does resizing a PDF lower its quality?
Text and vector drawings stay sharp because pages are placed as vector content. Scanned pages keep the resolution of the scan. Scaling a page down makes everything on it smaller, so very small print becomes harder to read.
Does Resize PDF upload my file?
No. The pages are resized in your browser and the file stays on your device.