Area: 1 B3 = 2 × B4 (B4 is half the area). Scaling factor: 1/√2 ≈ 0.7071 per side.
B3 is used for posters and book signatures, while B4 is popular for magazines and larger books. This tool helps you scale between them for professional design and production.
B4 = B3 × 2 · Scale factor = 1/√2 ≈ 0.7071 per side1 B3 sheet splits into exactly 2 B4 sheets (or 1 B4 = 0.5 B3).
📏 What is B3 Paper Size?
B3 is a medium-large paper size in the ISO 216 B-series. Its dimensions are 353 × 500 mm (13.9 × 19.7 inches), with an area of 0.1765 m². B3 is widely used for posters, book signatures, and professional printing. It sits between A3 (297 × 420 mm) and A2 (420 × 594 mm) in size, offering a versatile format for design and publishing. B3 is exactly double the area of B4, making it a common choice for book covers and medium-format posters.
📄 What is B4 Paper Size?
B4 is a medium paper size in the ISO 216 B-series. Its dimensions are 250 × 353 mm (9.8 × 13.9 inches), with an area of 0.08825 m². B4 is the go-to size for magazines, larger books, and professional printing projects. It's also popular for sheet music, calendars, and large-format envelopes. B4 is exactly half the area of B3, making it a natural choice for book signatures and magazine pages.
🧮 The Math: How B3 Becomes B4
The ISO 216 B-series is based on the geometric mean between A-series sizes. Each step down (B3 → B4) halves the area. The side lengths decrease by a factor of 1/√2 ≈ 0.7071.
- Width: 353 mm × (1/√2) ≈ 250 mm
- Height: 500 mm × (1/√2) ≈ 353 mm
- Area: 0.1765 m² ÷ 2 = 0.08825 m²
Formula: 1 B3 = 2 × B4 (in area). So, if you have 1 B3 sheet, you can split it into 2 B4 pages (or 1 B4 = 0.5 B3).
📊 Quick Conversion Table: B3 to B4
| B3 Sheets | B4 Equivalent | Scale factor (side) | Real‑world use |
|---|---|---|---|
| 0.5 B3 | 1 B4 | 100% (B4 = half B3) | Single magazine page |
| 1 B3 | 2 B4 | 70.7% (reduce) | Two-page magazine spread |
| 2 B3 | 4 B4 | 50% (half width/height) | Four-page booklet |
| 5 B3 | 10 B4 | 31.6% | Short book chapter |
| 10 B3 | 20 B4 | 22.4% | Book section |
| 25 B3 | 50 B4 | 14.1% | Short book |
| 50 B3 | 100 B4 | 10% | Magazine volume |
| 100 B3 | 200 B4 | 7.1% | Large book |
🖨️ Real‑World Examples: B3 to B4 in Action
- 📖 Book Publishing: B3 is used for book covers and large-format pages. When you need to produce B4 interior pages, this converter tells you exactly how many B4 pages fit into a B3 layout.
- 📰 Magazine Production: B4 is the classic magazine size. B3 is used for magazine covers and promotional materials. Understanding the scaling is essential for consistent design.
- 🎵 Sheet Music: B4 is a common size for sheet music and scores. B3 is used for enlarged versions for conducting and performance.
- 📅 Calendars: B4 is popular for wall calendars and planners. B3 is used for large-format calendar prints.
- 📬 Marketing Materials: B4 is used for professional brochures and catalogs. B3 offers more space for larger marketing content.
💡 Professional Tips for B3 to B4 Scaling
🎯 Resolution & Quality
When scaling from B3 to B4, if your original is 300 DPI, the resulting B4 will be ~424 DPI — actually higher quality! This is because you're concentrating the same pixels into a smaller area. For best results, design at 300 DPI at B3 for sharp B4 prints.
📐 Text Size Considerations
When scaling down from B3 to B4, text will appear smaller. For book and magazine layouts, ensure your font sizes are at least 11-12pt at B3 so they remain readable at B4 (approximately 8-9pt after scaling).
💰 Printing Efficiency
Printing 2 B4 pages from 1 B3 sheet is a common technique in book and magazine production. Many professional printers support B-series paper sizes — check your printer settings.
📂 Book Production
B3 is a common size for book covers and signatures. When planning a book, understanding how B3 converts to B4 helps with page layout and production planning.
❓ Frequently Asked Questions (B3 to B4)
Q: How many B4 sheets equal 1 B3?
A: Exactly 2 B4 sheets make 1 B3 in terms of area. You can fit two B4 pages on one B3 sheet.
Q: What is the scaling factor from B3 to B4?
A: Each side is scaled by 1/√2 ≈ 0.7071, meaning you reduce the width and height by 29.3%.
Q: Can I fit a B3 document onto a B4 sheet?
A: Yes, by scaling it down to 70.7% on each dimension. The document will fit, but text and details will be smaller.
Q: What is the difference in area between B3 and B4?
A: B3 has exactly double the area of B4 (0.1765 m² vs. 0.08825 m²).
Q: Is B3 bigger than B4?
A: Yes, B3 is larger. B3 is the next size up from B4. 1 B3 = 2 × B4.
Q: What is B3 used for?
A: B3 is used for posters, book covers, professional printing, and medium-format design.
Q: What is B4 used for?
A: B4 is used for magazines, sheet music, books, calendars, and professional printing.
Q: How does B‑series compare to A‑series?
A: B-series sizes are about 1.2× larger than A-series at the same number. For example, B4 (250 × 353 mm) is between A4 (210 × 297 mm) and A3 (297 × 420 mm) in size.
📈 Why Accurate B3‑to‑B4 Conversion Matters
Accurate scaling between B3 and B4 is essential for professional publishing, printing, and document management. Whether you're preparing a book, designing a magazine, or planning a marketing campaign, this tool ensures your documents fit perfectly every time. Inaccurate scaling can lead to wasted paper, misaligned designs, and costly reprints.
🌐 Global Standards & Professional Usage
The B‑series (ISO 216) is used alongside the A‑series in many countries. B-series sizes are particularly popular in book publishing, magazine production, and professional printing. This tool supports professional paper size conversions for users worldwide.
📐 The Full B‑Series Hierarchy
- B8 = 62 × 88 mm – small notepads, tags
- B7 = 88 × 125 mm – pocket notebooks, passports
- B6 = 125 × 176 mm – small books, notepads
- B5 = 176 × 250 mm – medium books, notebooks
- B4 = 250 × 353 mm – magazines, large books, sheet music
- B3 = 353 × 500 mm – posters, book covers, signatures
- B2 = 500 × 707 mm – large posters, book covers
- B1 = 707 × 1000 mm – large posters, banners
- B0 = 1000 × 1414 mm – display boards, billboards
Each step up doubles the area, making the system intuitive and easy to scale.
🔗 Explore More Paper & Print Tools
Check out our other converters: B3 to B2, B2 to B1, B1 to B0, A4 to A3, A3 to A4, Letter to A4, PX to MM, and DPI Calculator. All designed to make your print and design workflows smoother.