How to Print a PDF at Actual Size (100% Scale)
Use Actual Size or 100% when the dimensions inside a PDF must survive printing. A 50 mm reference should remain 50 mm on paper. This setting preserves scale; it does not make content outside the printer’s printable area printable.
Download the scale-check sheet
This one-page check file uses US Letter paper. Use matching Letter paper for this file. If you load A4, use the A4 option in the linked printer calibrator instead. The reference lines are 100 mm in the digital file; neither your screen zoom nor the browser preview is a physical measuring reference.
Print one controlled sample
- Open the PDF in a viewer with a print-size control. Check its page dimensions first.
- Select the intended printer, loaded paper size and orientation. Confirm the tray and media type in the driver.
- Choose Actual Size or 100%. Turn off Fit, Shrink and any additional scaling in the driver. A browser’s page margins and headers may behave differently from a PDF viewer.
- Print a single page. Measure the horizontal and vertical 100 mm references with a suitable ruler, from endpoint to endpoint.
- Record the viewer, paper setting and both readings before changing one setting at a time.
A 100 mm line prints at 94 mm
The observed ratio is 94 ÷ 100 = 0.94, or 94%. This is close to an A4-to-Letter full-sheet fit ratio, but the reading alone does not identify the cause. Check the PDF size, loaded sheet and both scaling controls first. A second reading of 100 mm vertically would point to unequal axes, so one uniform percentage would not correct both.
When Actual Size clips the edges
Keep the scale and move important content into the printable area, use a larger supported sheet, or tile the document. Switching to Fit may prevent clipping but changes dimensions. Borderless modes may also enlarge and crop, making them unsuitable for a ruler or calibration sheet.
What has been checked
The download’s page box and 100 mm vector references were inspected digitally on 2 November 2026. That verifies the file geometry, not the output of your printer. A physical sample remains necessary.
Sources and method
- Adobe Acrobat: adjust page size for printing: Actual Size, Fit and the difference between the page and the printable area.
- NIST: SI units of length: the exact conversion of one inch to 25.4 millimetres. Inch and point values below are calculated from the stated nominal dimensions.