Paper Size Converter
Convert paper size measurements between different units quickly and accurately
Convert Paper Size
Popular Paper Size Conversions
Quickly convert between the most commonly used paper sizes.
Understanding Paper Size Standards
Paper size conversions are essential for printing, publishing, and international business. Different regions use various paper size standards (A-series, US Letter, Legal, etc.), and understanding these conversions is crucial for document formatting, printing, and office work.
Common Paper Size Standards
ISO (A/B/C Series)
- A0-A6 - International standard sizes
- B4, B5 - Intermediate sizes
- C4, C5 - Envelope sizes for A-series papers
US/Canada Sizes
- Letter (8.5 × 11 in) - Standard US size
- Legal (8.5 × 14 in) - Legal documents
- Tabloid (11 × 17 in) - Posters, large prints
- Executive (7.25 × 10.5 in) - Memos, notepads
Common Applications
| Field | Paper Types | Typical Uses |
|---|---|---|
| Business | A4, Letter | Reports, letters, contracts |
| Publishing | A5, B5, Executive | Books, booklets, notepads |
| Posters | A3, Tabloid | Large prints, marketing |
| Mailing | C4, C5 | Envelopes for A4/A5 documents |
Conversion Tips
- A4 is slightly taller and narrower than US Letter
- 1 inch = 25.4 millimeters for size conversions
- ISO sizes halve in area from one size to the next (A3 = 2 × A4)
- Always check printer compatibility for non-standard sizes
Paper Size Conversions
| Conversion | Formula | Quick Answer |
|---|---|---|
| A4 to Letter | A4 (210 × 297 mm) ≈ Letter (216 × 279 mm) | A4 is taller, Letter is wider |
| Letter to A4 | Letter (8.5 × 11 in) ≈ A4 (8.27 × 11.69 in) | Letter is shorter, A4 is narrower |
| A3 to Tabloid | A3 (297 × 420 mm) ≈ Tabloid (279 × 432 mm) | A3 is slightly narrower and shorter |
| Tabloid to A3 | Tabloid (11 × 17 in) ≈ A3 (11.7 × 16.5 in) | Tabloid is wider, A3 is taller |
| A5 to Executive | A5 (148 × 210 mm) ≈ Executive (184 × 267 mm) | Executive is larger |
| C4 to A4 | C4 envelope fits A4 paper unfolded | C4 = 229 × 324 mm |
| C5 to A5 | C5 envelope fits A5 paper unfolded | C5 = 162 × 229 mm |
| B5 to A5 | B5 (176 × 250 mm) is larger than A5 (148 × 210 mm) | B5 is for books, A5 for booklets |
| Legal to A4 | Legal (8.5 × 14 in) ≈ A4 (8.27 × 11.69 in) | Legal is longer |
| A4 to Legal | A4 (210 × 297 mm) ≈ Legal (216 × 356 mm) | Legal is longer |
Our paper size conversion tool provides accurate conversions between all major international and US paper sizes, making it easy to format documents, print, and mail worldwide. Whether you're working in business, publishing, or design, our converter ensures precise paper size conversions for any application.
Paper Size Conversion Questions
Everything you need to know about paper size standards and conversions
What is the difference between A4 and Letter size?
A4 (210 × 297 mm) is slightly narrower and taller than Letter (216 × 279 mm). A4 is the international standard used worldwide, while Letter is primarily used in North America. A4 has an area of 62,370 mm² compared to Letter's 60,322 mm², making A4 about 3.4% larger.
Why does the A-series have those specific dimensions?
The A-series is based on a mathematical principle where each size is exactly half the area of the previous size. A0 has an area of exactly 1 square meter, and when folded in half along its longest side, it becomes A1. This continues through A1, A2, A3, A4, etc. The aspect ratio of √2:1 (approximately 1.414:1) is maintained throughout.
What paper sizes are used in different countries?
A4 is the standard in most of the world including Europe, Asia, and Australia. North America (US, Canada, Mexico) primarily uses Letter, Legal, and Tabloid sizes. The Philippines and some Latin American countries use a mix of both systems. Japan uses A-series but also has its own JIS B-series sizes.
How do I choose the right paper size for printing?
Consider your content and purpose: A4 for most documents and international use, Letter for North American business documents, A3 or Tabloid for posters and larger graphics, A5 for booklets and flyers, Legal for contracts and forms. Always check your printer's supported sizes and your audience's regional standards.
What is the difference between ISO and US paper series?
ISO series (A, B, C) are international standards with mathematical ratios, used globally. US series (Letter, Legal, Tabloid) evolved from historical practices and are primarily used in North America. ISO sizes maintain consistent √2:1 aspect ratios, while US sizes have varying ratios like 8.5:11 for Letter.
Can I print A4 documents on Letter paper?
Yes, but with some limitations. A4 is taller than Letter, so content may be cropped or scaled down. Most printers offer 'fit to page' or 'scale to fit' options. For professional documents, it's better to design specifically for your target paper size to avoid formatting issues.
What are B and C series paper sizes used for?
B-series sizes are intermediate sizes between A-series (e.g., B4 is between A3 and A4) and are often used for books, posters, and oversized documents. C-series sizes are designed for envelopes to hold A-series documents (e.g., C4 envelope holds A4 paper unfolded, C5 holds A4 folded once).
How do paper weights relate to paper sizes?
Paper weight (gsm - grams per square meter) is independent of size but affects thickness and quality. Standard weights: 80gsm for copy paper, 120-160gsm for brochures, 200-300gsm for business cards. Larger sizes use the same weight paper but weigh more overall due to increased area.
Have more questions? Contact us!