Paper Size Reference & Converter
The ISO 216 standard defines the A and B series paper sizes used worldwide. Each A-series sheet is exactly half the area of the previous size — A0 (841 × 1189 mm) down to A8 (52 × 74 mm) — all sharing the same √2 aspect ratio so that folding any sheet in half produces the next size with no wasted paper. The B series fills the gaps between A sizes and is commonly used for posters, books, and envelopes.
US paper sizes such as Letter (8.5 × 11 in), Legal (8.5 × 14 in), and Tabloid (11 × 17 in) follow a different, non-proportional convention rooted in historical printing practices. This tool lets you select any standard format and instantly see its dimensions in millimetres, centimetres, inches, and pixels at your chosen DPI — essential for print design, web graphics, and document layout work.
How it works
ISO A-series: width_n = 1000 × 2^(−1/4 − n/2) mm, rounded to nearest mm. Pixels = (dimension_mm / 25.4) × DPI. 1 inch = 25.4 mm exactly.
Use cases
- Configuring correct canvas size for a print-ready PDF or illustration
- Calculating pixel dimensions for a document scan at a given resolution
- Comparing ISO and US paper formats when ordering international print runs
- Setting up poster or banner designs in the correct physical dimensions
- Verifying envelope and insert size compatibility for direct-mail campaigns