Paper & resolution
Series
Resolution (DPI)
DPI = PPI. Pixels scale with DPI; 300 is common for print.
mm ⇄ px converter
Dimensions
Width × height. Click a row to copy it.
How many pixels should an A4 be? How many millimeters is B5? What's the print size of a business card? When you make print pieces, zines, flyers, or images, going back and forth between paper dimensions in millimeters and pixels is a constant chore. This paper size chart lets you pick a paper from the A series (A0–A8), the B series (JIS B0–B8), photo and postcard sizes (L, 2L, KG, postcard, reply postcard, instax mini), or cards (Japanese and US business cards, credit-card size), choose a resolution (DPI), and instantly see that paper's width and height in millimeters, centimeters, inches, and pixels. DPI offers the common print values 72, 96, 150, 300, 350, and 600 plus any custom value, and the pixel counts update immediately since they scale linearly with DPI (300 dpi is typical for print, 72/96 dpi for screen images). Click any row to copy its width × height, ready to paste into a new canvas in your image editor or into print specs. The mm⇄px converter at the bottom turns any length between millimeters and pixels at your chosen DPI. The A series is identical worldwide (ISO 216 = JIS), but the B series here uses the Japanese JIS B standard, so a JIS B5 differs in millimeters from an ISO B5 (see the FAQ). Whatever you enter is never sent anywhere; everything is computed entirely inside your browser.
How to use
- Pick a paper family: A series, B series, photo & postcard, or cards.
- Choose a paper size (e.g. A4, B5) and a resolution (DPI). Use 300 for print, 72/96 for screen images.
- Width × height appears in mm, cm, inch, and pixels. Click a row to copy it. Use the mm⇄px converter below for any length.
FAQ
Is the value I enter sent to a server?
No. All paper-size math runs inside your browser; nothing you enter is uploaded, stored, or transmitted. It works fully locally.
How many pixels is A4?
A4 is 210 × 297 mm, and the pixel count depends on resolution. At 72 dpi it's about 595 × 842 px, at 96 dpi about 794 × 1123 px, at print-ready 300 dpi it's 2480 × 3508 px, and at 350 dpi about 2894 × 4093 px. Switching the DPI in this tool updates the pixel count immediately.
How many mm is B5? Is it the same as ISO B5?
The B5 here is the Japanese JIS B5 at 182 × 257 mm. The international ISO B5 is 176 × 250 mm — a few millimeters different despite the same name. Since Japanese documents, notebooks, and zines commonly use JIS B sizes, this tool uses JIS B.
Are DPI and PPI different? What value should I use?
Strictly, DPI (printer dot density) and PPI (image pixel density) are different terms, but for turning a paper size into a pixel count they behave the same. Use 300 dpi for ordinary print, 350–600 dpi for high-detail print, and 72 or 96 dpi for screen and web. Pixel counts scale with DPI.
How do mm and pixels convert?
One inch is 25.4 mm, so pixels = mm ÷ 25.4 × DPI and mm = pixels ÷ DPI × 25.4. For example 210 mm at 300 dpi is 210 ÷ 25.4 × 300 ≈ 2480 px. Enter a value in the mm⇄px converter and it applies this formula at your chosen DPI.