- ISO A Series: Reference table for A0-A10 with mm, inches, 72 DPI and 300 DPI pixels, and common uses.
- ISO B & C: B-series and C-series envelope sizes (C3-C6, DL).
- US / North American: Letter, Legal, Tabloid, Executive, ANSI sizes.
- Custom Size: Enter width and height in mm, inches, cm, or points. Get conversions to all units plus pixel dimensions at 72, 150, and 300 DPI.
Paper Size Reference — Complete Guide
Whether you're designing for print, preparing documents, or ordering paper, knowing the exact dimensions is essential. Our Paper Size Reference provides comprehensive tables for ISO A/B/C series, US/North American sizes, and a custom calculator that converts between mm, inches, cm, points, and pixel dimensions at multiple DPI settings.
ISO A Series (A0–A10)
The ISO 216 standard defines the A series as the most widely used paper sizes globally. The system is elegantly designed:
- A0 has an area of exactly 1 square meter (841 × 1189 mm)
- Each subsequent size is exactly half the previous: A1 = A0/2, A2 = A1/2, etc.
- The aspect ratio is always 1:√2 (≈ 1:1.414), ensuring perfect scaling
- A4 (210 × 297 mm) is the global standard for everyday printing, forms, and documents
- A3 (297 × 420 mm) is common for large printouts and presentations
- A5 (148 × 210 mm) is popular for notebooks, booklets, and flyers
ISO B and C Series
The B series provides intermediate sizes between A sizes, often used for posters and books. The C series is specifically designed for envelopes:
- C4 (229 × 324 mm): Fits an unfolded A4 sheet
- C5 (162 × 229 mm): Fits a folded A4 or flat A5
- C6 (114 × 162 mm): Fits a folded A5 or flat A6
- DL (110 × 220 mm): Standard business envelope for A4 folded into thirds
US / North American Sizes
The United States and Canada use a different system:
- Letter (8.5 × 11 in / 216 × 279 mm): The standard everyday paper size in North America
- Legal (8.5 × 14 in / 216 × 356 mm): Used for legal documents, contracts
- Tabloid (11 × 17 in / 279 × 432 mm): Also called Ledger when landscape-oriented
- ANSI sizes: Engineering standard — ANSI A through ANSI E for technical drawings
DPI and Pixel Dimensions
When designing digital documents for print, you need pixel dimensions:
- 72 DPI: Screen resolution — suitable for web graphics and on-screen viewing
- 150 DPI: Draft/office quality — acceptable for everyday printing
- 300 DPI: Professional print quality — required for commercial printing, photos, and high-quality output
Formula: Pixels = Size in inches × DPI or Pixels = Size in mm ÷ 25.4 × DPI
Custom Size Calculator
Enter any dimensions in mm, inches, centimeters, or points (1/72 inch) to instantly convert to all other units and see pixel dimensions at 72, 150, and 300 DPI.
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