A paper size chart for printer use is a reference table that lists every standard paper size in millimetres, centimetres, and inches, alongside its pixel dimensions at common print resolutions such as 72, 150, 300, and 600 DPI. The three families most printers need are the international A series defined by ISO 216, the supplementary B series defined by ISO 216, and the North American ANSI/US sizes such as Letter, Legal, and Tabloid. A4, the most common sheet worldwide, measures 210 × 297 mm (8.27 × 11.69 in) and is the default page size in most countries outside the United States and Canada. US Letter, the North American default, measures 8.5 × 11 in (215.9 × 279.4 mm). Knowing the exact dimensions — and the matching pixel count at your target DPI — is the difference between a print job that fits the page and one that gets cropped, scaled, or rejected by the printer driver.
Most of the confusion around printer paper sizes comes from the clash between the international ISO standard and the older North American sizes. Designers, students, and office workers frequently need to know both, especially when a file is shared across regions or sent to a commercial printer. That is why a single reference that shows millimetres, centimetres, inches, and pixels in one place is so useful. The Paper Sizes Chart tool does exactly that, letting you look up any A, B, or US size and instantly see the pixel width and height at the DPI you choose.
The Standard Paper Size Families
Three families cover almost every printer paper size you will encounter. Understanding which family a size belongs to tells you a lot about its proportions and intended use.
The A series, defined by ISO 216, is the international standard used by virtually every country except the United States and Canada. Each size in the series has a fixed aspect ratio of √2:1, which means halving an A size along its longer side produces the next size down. A0 is the largest at 841 × 1189 mm; A1 is 594 × 841 mm; A2 is 420 × 594 mm; A3 is 297 × 420 mm; A4 is 210 × 297 mm; A5 is 148 × 210 mm; and A6 is 105 × 148 mm. This predictable ratio is what makes A-series paper so easy to scale in design software without distortion.
The B series, also defined by ISO 216, is less common in everyday printing but appears in posters, books, and envelopes. B sizes sit geometrically between two consecutive A sizes. B5, for example, is 176 × 250 mm, a popular size for books and notebooks. B4 is 250 × 353 mm, often used for larger books and posters.
The US series, defined by ANSI (American National Standards Institute), is the default in North America. US Letter (8.5 × 11 in), Legal (8.5 × 14 in), and Tabloid or Ledger (11 × 17 in) are the three sizes you will handle most often. There is no consistent aspect ratio across US sizes, which is why scaling US paper for international use sometimes produces awkward margins.
Common Printer Paper Sizes at a Glance
| Name | Millimetres | Centimetres | Inches | Standard Use |
|---|---|---|---|---|
| A4 | 210 × 297 | 21.0 × 29.7 | 8.27 × 11.69 | Default office paper, international |
| A3 | 297 × 420 | 29.7 × 42.0 | 11.69 × 16.54 | Posters, drawings, spreadsheets |
| A5 | 148 × 210 | 14.8 × 21.0 | 5.83 × 8.27 | Flyers, booklets, notebooks |
| B5 | 176 × 250 | 17.6 × 25.0 | 6.93 × 9.84 | Books, magazines |
| US Letter | 215.9 × 279.4 | 21.59 × 27.94 | 8.5 × 11 | Default office paper, North America |
| US Legal | 215.9 × 355.6 | 21.59 × 35.56 | 8.5 × 14 | Legal documents, contracts |
| Tabloid / Ledger | 279.4 × 431.8 | 27.94 × 43.18 | 11 × 17 | Newspapers, engineering drawings |
This table is a quick reference for the sizes you will pick from most often. For pixel dimensions at a specific DPI, the tool gives you an exact answer in real time.
How to Use the Paper Sizes Chart Tool
The Paper Sizes Chart tool is designed for a single, practical task: look up any paper size and convert it to pixels at any DPI. Here is how to get from a blank page to a finished pixel value.
- Open the Paper Sizes Chart tool in your browser. The reference table loads immediately with the A series, B series, and US group, each row showing dimensions in millimetres, centimetres, and inches.
- Scan the table to find the paper size you need. If you are unsure whether to use A4 or US Letter, both appear side by side, so you can compare exact dimensions before choosing.
- In the converter section, open the dropdown and pick the paper size you want. The exact millimetre, centimetre, and inch values load automatically so you can confirm you picked the right one.
- Type the resolution you need in the DPI field. Use 300 for standard print quality, 600 for high-resolution photo or art prints, and 72 for screen work such as web graphics or PDF previews.
- Read off the pixel width and pixel height that appear next to your chosen DPI. These are the exact canvas dimensions to set in Photoshop, Illustrator, InDesign, GIMP, or any layout program.
- Match the pixel result to the physical dimensions shown alongside it, and you have everything you need to set up a print-ready document, export a PDF, or configure a printer driver.
Converting Paper Size to Pixels for Printing
Pixel dimensions for a printed page come from a simple formula: pixels = physical size (in inches) × DPI. A US Letter page is 8.5 × 11 in, so at 300 DPI it is 8.5 × 300 by 11 × 300, which is 2550 × 3300 pixels. At 72 DPI, the same sheet is 612 × 792 pixels, the classic PDF point-based page size. The relationship is the same for A4, A3, and every other size — only the starting physical dimensions change.
Choosing the right DPI matters because it controls how sharp the print looks. 300 DPI is the industry standard for offset and digital printing of text and photos. 150 DPI is acceptable for large-format posters viewed from a distance. 72 DPI is the screen standard and is not intended for print, though it is fine for draft copies and on-screen review. When in doubt, design at 300 DPI and downsample later if you need a smaller file.
Setting Up a Print-Ready Canvas in Common Software
Once you have the pixel dimensions, setting up the canvas in your design program is straightforward. In Photoshop, choose File > New, switch the units to pixels, and type the width and height the tool gave you. Set the resolution to the same DPI you used in the converter so the print size matches the canvas. In InDesign and Illustrator, work in millimetres or inches using the dimensions from the reference table; the software handles pixel output for you when you export. For PDFs, turning JPGs into a single PDF in your browser requires the same page size match, so picking the correct paper dimension up front avoids awkward rescaling later.
Choosing Between A4 and US Letter
If you are printing for an international audience, A4 is almost always the safer choice — it is the default in the UK, Europe, Asia, Africa, most of South America, and Oceania. If you are printing for a US or Canadian audience, US Letter is the default and most home and office printers will assume it. Mixing the two is the single most common source of cropped or scaled printouts. The two sizes are close but not interchangeable: A4 is 210 mm wide while Letter is 215.9 mm wide, and A4 is 297 mm tall while Letter is 279.4 mm tall. The Paper Sizes Chart lets you confirm the exact difference in any unit you prefer before you commit to a layout.
Working with Margins, Bleed, and Trim
Bleed is the extra image area that extends beyond the trim line so that any slight misalignment during cutting does not leave a white edge. The ISO 216 standard and most commercial printers recommend at least 3 mm of bleed on every side for A and B series, and 0.125 in (about 3.175 mm) for US sizes. If your document is going to a commercial printer, add the bleed to your canvas before placing any artwork, and keep all critical text and images inside the safe margin, typically another 3 mm inside the trim line. The paper size dimensions in the chart refer to the trim size; your working file should be larger to accommodate bleed. Once your file is exported, tools such as Resize PDF can scale finished pages to a different paper size if you need a quick adjustment, and Crop PDF can trim margins after the fact.
Quick Reference: A4 in Pixels at Common DPIs
A4 is 210 × 297 mm, or 8.27 × 11.69 in. The pixel dimensions therefore change with DPI: at 72 DPI the canvas is 595 × 842 pixels, the standard PDF screen size; at 150 DPI it is 1240 × 1754 pixels, a common draft-print resolution; at 300 DPI it is 2480 × 3508 pixels, the standard print-resolution canvas; and at 600 DPI it is 4960 × 7016 pixels, used for high-end photo and art prints. The Paper Sizes Chart tool gives you the exact pixel value for any DPI you type, so you do not need to memorize or calculate these by hand.
Why a Reference Chart Beats Memorisation
Paper sizes are stable — A4 has been 210 × 297 mm since the ISO 216 standard was first published in 1975, and US Letter has been 8.5 × 11 in since the American National Standards Institute adopted it in the 1990s — but the number of sizes a designer might need in a single day is large. A reference chart removes the need to remember whether B4 is larger or smaller than A3, whether Legal is wider or taller than Letter, or what Tabloid measures in millimetres. Pair that reference with a pixel converter, and you can move from a quick question to a print-ready canvas in seconds without second-guessing any number.
If you're weighing options, Paper Size Chart for Printer: Pixel Conversion at Any DPI covers this in detail.