Use 100% when the original physical dimensions matter. Use Fit when keeping the whole page inside the available area matters more than its exact size.
Start with the job, not the setting
For a reading copy of a checklist, a small change in size may be acceptable. For a cut-out template or a ruler, the same change can make the output unusable. Decide whether your priority is physical size or complete visibility before opening the print dialog.
Adobe’s Fit option can enlarge small pages and reduce large ones. Its shrink-only option leaves small pages unchanged. Custom Scale lets you supply a percentage. The available wording depends on the application you use.
Why 100% can still lose an edge
Imagine a 210 mm wide design printed on a 210 mm wide sheet. If the printer cannot mark the outer 5 mm on either side, only 200 mm of width is usable. The full-size design is 10 mm wider than that usable region. Keeping its size cannot also keep every edge visible.
One solution is larger paper followed by trimming. Another is changing the layout to keep important marks away from the edges. Shrinking is useful only if the change in dimensions is acceptable for the task.
What a percentage does to your layout
A percentage applies to every linear dimension: text, margins, boxes and reference marks. At 96%, a 100 mm line becomes 96 mm and a 50 mm box becomes 48 mm. It does not selectively shrink the blank margin while leaving the useful content untouched.
The scale calculator predicts rectangle dimensions. It cannot inspect the content of your PDF, detect the printer’s actual margins or verify the physical output.
Use a small test before a large batch
Print a page containing a known measurement. Measure that mark with a physical ruler, not against the screen. A screen’s zoom percentage is a viewing setting and should not be treated as a measurement of the printed sheet.
If the test is wrong, compare the document size, chosen paper size and scaling settings. Change one setting at a time so that the result tells you what helped. See how to calculate a correction when the discrepancy is uniform.
A quick decision guide
- Reference marks or exact-size templates: begin at 100%, then measure.
- A reading copy with no dimensional requirement: a fit can preserve the visible content.
- An exact-size page that clips: investigate larger paper or a revised layout.
- An image that must fill a different-shaped frame: decide what can be cropped or left blank.
Use our measurement-sheet workflow when you need evidence from the actual print instead of relying on the preview.
Worked examples use the formulas stated on this page. These are mathematical examples, not physical printer tests.
Print-setting reference: Adobe’s PDF scaling guide.