Paper Size Comparison
Compare ISO A, JIS B, and Letter dimensions and calculate a fit-to-page scale.
How to use
- Choose the source and target paper sizes.
- Review short-edge and long-edge dimensions and the fit scale.
- Enter the scale in your print settings and check the actual preview including printer margins.
When to use this tool
Check dimensions and scale when fitting a document onto another paper size. Compare ISO A, Japanese JIS B, and Letter sizes while preserving the source aspect ratio.
Inputs and settings
Result
Example input and actual output
- Source paper: A4
- Target paper: A3
Source (mm): 210 × 297 Target (mm): 297 × 420 Fit scale (%): 141.414141
A4 at 210×297mm fits A3 at 297×420mm at approximately 141.414%. Taking the smaller edge ratio avoids overflow caused by rounded standard dimensions. Printer margins are not subtracted.
| Paper | Short edge | Long edge |
|---|---|---|
| A3 | 297 | 420 |
| A4 | 210 | 297 |
| A5 | 148 | 210 |
| JIS B4 | 257 | 364 |
| JIS B5 | 182 | 257 |
| Letter | 215.9 | 279.4 |
Scope and limitations
Aligns short and long edges and calculates the scale that fits inside the target. Printer margins and printable areas are excluded.
Next step and alternatives
Fold Position Calculator — Calculate panel widths and fold positions for the selected sheet.
Frequently asked questions
Are B sizes ISO B or JIS B?
JIS B. B4 is 257×364mm and B5 is 182×257mm; these differ from ISO B dimensions.
Does this guarantee nothing is clipped when printing?
It is a geometric scale for the whole sheet. Printable area, borderless settings, and margins in the source document can change the actual result.
Which ratio is used when short-edge and long-edge ratios differ?
The smaller edge ratio is used to avoid exceeding the paper dimensions, including differences caused by rounded standard sizes.
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