A paper size chart for printer use lists the exact dimensions of standard formats like A4, A3, US Letter, and Legal in millimetres, centimetres, inches, and pixels, so you can set up a print-ready canvas or export file without guessing. A4, the most widely used printer size, is 210 × 297 mm (8.27 × 11.69 in), and at the print-standard 300 DPI it resolves to 2480 × 3508 pixels. A single chart that shows millimetre, centimetre, inch, and pixel values at a chosen DPI removes the need to run four separate conversions before laying out a document.
Most people search for a paper size chart when they are about to print something, export a PDF to a specific page size, or build a design file at the right dimensions. The problem is that printer software, design software, and online tools all describe the same page in different units. A Photoshop canvas asks for pixels at a DPI, a Word document uses inches, and a PDF often references millimetres. A unified chart that shows all four units on one page is the fastest way to line them up.
Standard Printer Paper Sizes at a Glance
Three families cover almost every printer you will encounter. The ISO 216 A-series is the international standard, used in Europe, Asia, and most of the Americas for office and home printing. The ISO 216 B-series covers larger formats such as posters and book covers. North American sizes — Letter, Legal, and Tabloid — dominate in the United States and Canada.
| Size | Millimetres | Centimetres | Inches |
|---|---|---|---|
| A4 | 210 × 297 | 21.0 × 29.7 | 8.27 × 11.69 |
| A3 | 297 × 420 | 29.7 × 42.0 | 11.69 × 16.54 |
| A5 | 148 × 210 | 14.8 × 21.0 | 5.83 × 8.27 |
| US Letter | 215.9 × 279.4 | 21.59 × 27.94 | 8.5 × 11.0 |
| US Legal | 215.9 × 355.6 | 21.59 × 35.56 | 8.5 × 14.0 |
| US Tabloid (A3 alt.) | 279.4 × 431.8 | 27.94 × 43.18 | 11.0 × 17.0 |
These values come straight from the ISO 216 standard for A-series sizes and from the American National Standards Institute for the US group. Knowing the exact millimetre and inch values is what lets you translate between a metric layout and an imperial printer driver without rescaling.
How to Use a Paper Size Chart for Printer Setups
- Scan the reference table to find your paper size in the A series, B series, or US group, with dimensions shown in millimetres, centimetres, and inches.
- Open the Paper Sizes Chart converter and choose a paper size from the dropdown to load its exact dimensions.
- Type the resolution you need in the DPI field — 300 is the standard for print output, 72 works for screen-only PDFs — to see the pixel width and height update instantly.
- Read the pixel result alongside the millimetre, centimetre, and inch values to set up your canvas in Photoshop, Illustrator, InDesign, Word, or your print driver.
- Copy the matching width and height into your design or export preset, and confirm the bleed and margins match the printer's requirements before saving the final file.
The tool handles every standard format in the same workflow, so once you have used it for A4 you can switch to Letter, Legal, or A3 without learning a new method.
Why 300 DPI Is the Print Standard
300 DPI means 300 dots of ink per linear inch, which translates to roughly 118 dots per centimetre. At normal reading distance of 30–40 cm, this is the resolution at which individual dots become invisible to the naked eye on coated paper. Below 200 DPI text starts to look soft and halftone patterns show through, especially on images. The widely cited print guideline of 300 DPI traces back to offset printing conventions that digital printers have largely inherited.
For screen use, 72 DPI (sometimes 96 DPI on Windows displays) is the standard because monitors render one device pixel per CSS pixel at 1× scaling. A4 at 72 DPI is 595 × 842 pixels, which is exactly what a web preview needs. Pushing a screen design to 300 DPI just inflates the file size without any visual gain on the monitor.
Converting Paper Sizes to Pixels at Common DPIs
The pixel formula is simple: multiply each dimension in inches by the DPI. For example, A4 is 8.27 × 11.69 inches, so at 300 DPI the width is 8.27 × 300 = 2481 pixels, rounded to 2480 in most software, and the height is 11.69 × 300 = 3507 pixels, rounded to 3508. At 150 DPI the same page becomes roughly 1240 × 1754 pixels, which is what many office printers use in draft mode to save ink.
| Paper Size | 72 DPI (px) | 150 DPI (px) | 300 DPI (px) |
|---|---|---|---|
| A4 (210 × 297 mm) | 595 × 842 | 1240 × 1754 | 2480 × 3508 |
| A3 (297 × 420 mm) | 842 × 1191 | 1754 × 2480 | 3508 × 4961 |
| A5 (148 × 210 mm) | 420 × 595 | 874 × 1240 | 1748 × 2480 |
| US Letter (8.5 × 11 in) | 612 × 792 | 1275 × 1650 | 2550 × 3300 |
| US Legal (8.5 × 14 in) | 612 × 1008 | 1275 × 2100 | 2550 × 4200 |
If you need values for a different DPI or for B-series and C-series sizes, the converter inside the Paper Sizes Chart returns them without manual arithmetic. For the underlying ISO definitions, the ISO 216 standard page on iso.org is the authoritative reference.
Choosing the Right Size for Print, Web, and Office
Office documents, invoices, and most everyday printing default to A4 in metric regions and US Letter in the United States. Legal (8.5 × 14 in) is reserved for contracts, legal pads, and longer forms. A3 and Tabloid (11 × 17 in) suit spreadsheets, engineering drawings, posters, and folded brochures. A5 is a popular size for booklets, flyers, and pocket notebooks because A4 folded in half produces exactly A5 dimensions, a useful property when planning multi-page layouts.
For screen-first output such as ebooks, presentations, and reports viewed on a monitor, the physical paper size is less important than the aspect ratio. An A4 PDF and a US Letter PDF look nearly identical on a 16:9 laptop screen, but they print very differently if sent to a printer set to a different paper tray.
Quick Reference: When to Pick Each Size
- A4: default for letters, reports, schoolwork, and CVs outside North America.
- US Letter: default for the same use cases inside the United States and Canada.
- US Legal: contracts, legal forms, accounting worksheets that need extra length.
- A3 / Tabloid: spreadsheets, blueprints, posters, and large flyers.
- A5: booklets, invitations, folded leaflets, pocket guides.
- B4 / B5: posters, envelopes, and book covers in regions that use the B-series.
Linking the Chart to Other PDF Tools
Once you know the right size, the rest of the workflow usually involves PDFs. A correctly sized A4 PDF can be sent straight to a printer, but if the page was originally scanned at the wrong size you can fix it in your browser. The Resize PDF tool rescales every page to A4, Letter, or Legal without uploading the file. The guide on cropping a PDF permanently covers how to trim unwanted edges from scans that came in at the wrong dimensions. For multi-page output, the Merge PDF tool combines several files into one document while preserving the original page sizes.
Common Pitfalls When Setting Print Dimensions
The most frequent mistake is confusing DPI with PPI. Both stand for "dots/pixels per inch," and in everyday use they are treated as the same number, but printers describe output resolution in DPI and screens describe input resolution in PPI. A 300 DPI print of an A4 image at 2480 × 3508 pixels is the same physical size as a 300 PPI image with the same pixel dimensions.
Another common issue is rounding. A4 is exactly 210 × 297 mm, but in inches it is 8.2677 × 11.6929, and rounding to 8.27 × 11.69 is what most software displays. If you need pixel-exact output, use the converter rather than chaining manual roundings. Bleed is a separate concern: most print jobs require 3 mm of bleed on each edge, so the trim size is the chart value but the final canvas is 6 mm larger on every side.
Setting Up a Print-Ready File from the Chart
Start by picking the size and DPI you need from the chart. For a print-ready A4 PDF at 300 DPI, set the canvas to 2480 × 3508 pixels, or 210 × 297 mm with 3 mm bleed on each edge. Match the colour profile to your printer (CMYK for inkjet and laser, RGB only for screen output), embed all fonts, and export to PDF/X-1a or PDF/X-3 if the print shop requests it. The chart is only the first step, but getting the dimensions right at the start prevents rescaling artefacts later.