Paper Size Reference & Converter
指导
Paper Size Reference & Converter
Look up any standard paper size across the ISO, ANSI, and JIS systems and see its dimensions in millimeters, centimeters, inches, points, picas, and pixels at any common print or screen DPI. Switch to custom mode to enter your own width and height in mm, cm, inches, points, or pixels and instantly find the closest standard sizes, ranked by how exact the match is.
如何使用
- 选择 Look up a standard size and pick a paper from the dropdown (organized by series: ISO A/B/C, ANSI, JIS B, envelopes, photo, business cards).
- Or choose Find closest match for custom dimensions and enter a width and height in any supported unit.
- 选择 肖像 或 Landscape to swap the orientation.
- 设置 分辨率（DPI） to control how pixel dimensions are computed (72 for PDF/screen, 96 for web, 300 for print, 600 for high-res print).
- Read the dimensions table for width, height, and diagonal in all supported units. In custom mode, the closest-match table ranks the five nearest standard sizes with an exactness badge.
特征
- ISO 216 series – Complete A0–A10, B0–B10, and C0–C10 envelopes used worldwide outside North America.
- ANSI / North American – Letter, Legal, Junior Legal, Half Letter, Executive, Tabloid (ANSI B), Ledger, ANSI C/D/E.
- Japanese JIS B series – JIS B0–B10, which are slightly larger than ISO B equivalents.
- Envelope sizes – DL, C6/C5, US #9, #10, Monarch, A2/A6/A7 card envelopes.
- Photo & cards – 4×6, 5×7, 8×10 photo prints plus US and EU business card formats.
- All units – Width, height, and diagonal in millimeters, centimeters, inches, points, picas, and pixels.
- Configurable DPI – Choose 72, 96, 150, 300, or 600 DPI for accurate pixel output for screen or print.
- Portrait / Landscape toggle – Swap orientation without re-entering dimensions.
- Aspect ratio & area – Reduced ratio plus decimal ratio and area in cm² and in².
- Closest-match finder – Enter custom dimensions and get a ranked top-five list with exactness badges (Exact, Very close, Similar, Rough).
- Runs in your browser – Dimensions and matches compute instantly with no data leaving your device.
常问问题
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What is the relationship between ISO A-series paper sizes?
Each ISO A size has an area exactly half of the next larger one, and they all share the same aspect ratio of 1:√2 (about 1:1.4142). Folding an A4 sheet in half produces two A5 sheets; folding A5 in half produces A6; and so on. The base size A0 has an area of exactly one square meter, which is how every other A size is derived. This geometric property means scaling between any two A sizes preserves layout proportions without cropping.
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How is a PostScript point different from a typographic point?
A PostScript point (also called the DTP or computer point) is defined as exactly 1⁄72 of an inch (about 0.3528 mm) and is the standard used by PDF, CSS, and modern design software. The older typographic point used by traditional printers came in several flavors — the most common being the American Pica point at about 0.3515 mm and the Didot point used in continental Europe at about 0.3759 mm. Any modern paper-size tool uses the PostScript point because it matches what software and printer drivers actually produce.
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Why do pixel dimensions depend on DPI?
DPI (dots per inch) maps a physical inch on paper to a number of pixels in a digital image. At 72 DPI, one inch becomes 72 pixels; at 300 DPI, one inch becomes 300 pixels. Because paper sizes are defined in physical units (millimeters or inches), their pixel equivalents only exist relative to a chosen DPI. 72 DPI is the historical screen and PDF default, 96 DPI is the CSS reference for the web, 300 DPI is the print-ready standard for photos and brochures, and 600 DPI is used for high-fidelity prints like fine art and book interiors.
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How do JIS B sizes differ from ISO B sizes?
Both share the 1:√2 aspect ratio, but their base size differs. ISO B0 is the geometric mean of A0 and A0×2 (841 × 1189 mm and 1189 × 1682 mm), giving 1000 × 1414 mm. JIS B0 is defined so its area is exactly 1.5 m², giving 1030 × 1456 mm. Every JIS B size is therefore slightly larger than its ISO B counterpart, which matters when ordering pre-cut paper or envelopes from suppliers in different regions.
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What is a pica and where is it still used?
A pica equals 12 points, or 1⁄6 of an inch (about 4.233 mm). It remains the standard column-width and line-length unit in print typography and is still used in newspaper layout, magazine design, and many page-layout programs like Adobe InDesign and QuarkXPress. CSS does not natively use picas, but the relationship to points and inches makes them easy to convert when bringing print designs to the web.
