Print the matching A4 or US Letter test PDF at 100%. Measure the horizontal and vertical 100 mm marks between their endpoint centers. Record both values before changing a setting.
Choose the PDF that matches the loaded paper
The A4 test sheet has a 210 × 297 mm PDF page. The Letter version has an 8.5 × 11 inch page. The measurement marks are the same size in both files. Choosing the matching version avoids introducing a paper conversion into the test.
Download the PDF itself and print that document. Printing the web page, a screenshot or an image of the PDF adds another opportunity for resizing. Select one page per sheet and check that the application and printer settings agree on the paper.
Measure a line, not the page on your screen
Use a physical ruler. The short ticks cross the endpoints of each 100 mm line. Measure from the center of one endpoint tick to the center of the other; the outer edges of the ink are not the intended endpoints. The square is 1 inch wide and high, measured between line centers, and provides a second unit check.
A physical ruler also has finite precision. Record a sensible reading rather than inventing extra decimal places. A slight difference close to the limits of your measurement method needs a repeat check before a correction.
Interpret the pair of measurements
| Horizontal / vertical | What to investigate |
|---|---|
| 100 / 100 mm | Dimensions match at these locations. Check position and edges separately. |
| 96 / 96 mm | Consistent reduction. Inspect scaling and repeat at the intended setting. |
| 96 / 99 mm | Unequal change. One uniform percentage will not fix both directions. |
These examples describe geometry; they do not identify a particular hardware fault. The worksheet cannot certify printer accuracy over the whole page or across repeated prints.
Make one adjustment and repeat
If the change is uniform and repeatable, the print correction formula gives a candidate setting. For example, a 96 mm line intended to be 100 mm at a current 100% setting suggests 104.17% for the next test. An enlargement can clip other content, so inspect the page edges too.
Write the application, paper and setting on each test. Keep the unmodified PDF as the reference. Do not resize the reference file to compensate for one printer and then use it as a universal calibration document.
What has been checked
The PDF page dimensions and reference geometry are verified in the generated files. Their rendered layouts are inspected for readability. No physical printer test or professional calibration is claimed.
Worked examples use the formulas stated on this page. These are mathematical examples, not physical printer tests.