Paper Size Comparison: See A4, Letter, A5 and More at Scale
Select formats to compare their proportions at one visual scale, then calculate how a full document rectangle fits onto another sheet. The drawing is useful for choosing a page size; it is not an actual-size ruler on your screen.
Compare dimensions and calculate a fit
Choose the sizes to compare
| Size | Millimetres | Inches | Area vs A4 | Aspect ratio |
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Will it fit? Scale calculator
Read three different results
- Dimensions describe the nominal width and height of the sheet.
- Area describes the surface available before margins. Similar area does not imply the same shape.
- Fit percentage is the smaller of target width ÷ document width and target height ÷ document height, multiplied by 100. The tool compares the selected portrait dimensions without allowing for printer margins.
Worked example: A4 onto Letter
A4 is 210 × 297 mm. Letter is 215.9 × 279.4 mm. The width permits 215.9 ÷ 210 = 102.81%, but the height permits only 279.4 ÷ 297 = 94.07%. Height is the limiting direction, so a whole A4 rectangle needs to shrink to about 94.1% before printer margins are considered.
A 100 mm feature becomes about 94.1 mm. If the feature must stay 100 mm, use matching paper, crop only expendable surroundings, or tile the document across sheets.
Why Letter to A4 gives a different answer
For Letter onto A4, the width ratio is 210 ÷ 215.9 = 97.27%; the height has room to spare. This is not the reciprocal of 94.07%, because a different edge limits the fit. A print application’s Fit setting can shrink further to the driver’s printable area.
Similar names that need a dimension check
- A5 versus half A4: nominal A5 is 148 × 210 mm. Halving A4 produces 148.5 × 210 mm panels before trimming.
- ISO B5 versus JIS B5: 176 × 250 mm and 182 × 257 mm respectively. A preset labelled only B5 is ambiguous.
- Half Letter versus A5: Half Letter is 139.7 × 215.9 mm, or 5.5 × 8.5 inches; it is not interchangeable with A5.
- 4 × 6 inches versus 100 × 150 mm: the inch size converts to 101.6 × 152.4 mm. Check the actual photo-paper package.
Choose the next action
Use the unit converter to express a known sheet in inches or PDF points. Use the fit planner when you need edge insets or optional rotation. Use the image PPI calculator for raster detail; a paper’s physical size does not define its pixel count.
Sources and method
ISO 216 covers trimmed A- and B-series sizes. Ricoh’s size specifications distinguish JIS B5. The inch conversion uses 25.4 mm per inch. Adobe documents print page sizing. Percentages are geometric calculations, not observed print results.