Paper size scale calculator (A3 to A4, A4 to Letter)
Enter the result in the scale option of your printer or copier to fit the whole page on the other sheet.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter from size and to size.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Scale = the smaller of (target width ÷ source width) and (target length ÷ source length) × 100, same orientation.
Example
Inputs: From size = A3 (297 × 420 mm), To size = A4 (210 × 297 mm). Result: Print scale: 70.7%; Page size after scaling: 210 × 296.97 mm; Blank space across the width: 0 mm.
Limits and caveats
- Ignores the printer unprintable margins; you may need a few percent less.
Questions about this tool
What is the scale from A3 to A4?
About 70.7%; copiers usually show it as 71%.
What scale prints an A4 file on Letter?
About 94%, so the whole page shows without clipping.
Why is there blank space?
The two sheets have different shapes, so the page fills one side and leaves a gap on the other.