Paper-size converter
Look up a standard paper size in millimetres, inches and pixels at 300 DPI — A-series from A6 to A0, plus US Letter, Legal and Tabloid — for setting up a document or print-ready design.
Result
Width
Height
Width
Height
Width at 300 DPI
Height at 300 DPI
How to use this tool
- Choose a paper size.
- Read its dimensions in millimetres and inches.
- Use the 300 DPI pixel size as the canvas for a print-quality design at that size.
Assumptions
- Uses the standard published dimensions for each size — some printers/trimmers have very small tolerances that can differ by a millimetre or two.
Technical details: what the fields mean
- Paper size
paperSize - A standard paper size — A4 and A3 are common in most of the world; Letter and Legal are standard in the US and Canada.
Methodology
Looks up the standard dimensions for the chosen paper size from the international ISO 216 A-series and North American paper sizes. Inches = mm ÷ 25.4; pixels at 300 DPI = inches × 300, rounded.
Worked example
A4
Inputs: Paper size: A4
Result: 210.0mm × 297.0mm (8.27in × 11.69in); 2480 × 3508 px at 300 DPI.
A6 — postcard and flyer size
Inputs: Paper size: A6
Result: 105 × 148mm (4.13 × 5.83in); 1240 × 1748 px at 300 DPI.
US Letter for a North American client
Inputs: Paper size: Letter
Result: 215.9 × 279.4mm (8.5 × 11in); 2550 × 3300 px at 300 DPI.
Scaling an A4 design up to A3
Inputs: Paper size: A3
Result: 297 × 420mm; 3508 × 4961 px. A3's short side equals A4's long side, so the design scales by √2 ≈ 1.41 with no change in shape.
Practical guidance
- A-series sizes halve in area each step up (A4 is half of A3, which is half of A2) — useful for scaling a design between sizes.
- Every A size has the same 1 : √2 shape, so a design scales between A sizes without cropping; Letter has a different shape.
- For professional printing, add the printer's bleed (often 3mm per edge) to the canvas — check their spec.
Common mistakes
- Confusing US Letter (215.9×279.4mm) with A4 (210×297mm) — they're similar but not the same, which can cause printing/formatting issues when a document made for one is printed on the other.
FAQs
What size is A4 paper in inches?
8.27 × 11.69 inches (210 × 297mm).
Is US Letter the same as A4?
No — Letter is 215.9 × 279.4mm, slightly wider and shorter than A4's 210 × 297mm.
How many pixels is A4 at 300 DPI?
2480 × 3508 pixels.
Last reviewed: 2026-09-25
Uses standard published dimensions — always confirm your specific printer or paper stock matches these exactly if precision matters.
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