Area: 1 B4 = 2 × B5 (B5 is half the area). Scaling factor: 1/√2 ≈ 0.7071 per side.
B4 is used for magazines and large books, while B5 is used for notebooks and smaller publications — this tool helps you scale between them.
B5 = B4 × 2 · Scale factor = 1/√2 ≈ 0.7071 per side1 B4 sheet splits into exactly 2 B5 sheets (or 1 B5 = 0.5 B4).
📏 What is B4 Paper Size?
B4 is a medium-large 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 widely used for magazines, large books, and professional printing. It sits between A4 (210 × 297 mm) and A3 (297 × 420 mm) in size, offering a versatile format for publications and design. B4 is exactly double the area of B5, making it a common choice for magazine spreads and book signatures.
📄 What is B5 Paper Size?
B5 is a medium-small paper size in the ISO 216 B-series. Its dimensions are 176 × 250 mm (6.9 × 9.8 inches), with an area of 0.044 m². B5 is the go-to size for notebooks, journals, and smaller publications. It's also popular for pocketbooks and personal planners. B5 is exactly half the area of B4, making it a natural choice for portable and everyday use documents.
🧮 The Math: How B4 Becomes B5
The ISO 216 B-series is based on the geometric mean between A-series sizes. Each step down (B4 → B5) halves the area. The side lengths decrease by a factor of 1/√2 ≈ 0.7071.
- Width: 250 mm × (1/√2) ≈ 176 mm
- Height: 353 mm × (1/√2) ≈ 250 mm
- Area: 0.08825 m² ÷ 2 = 0.044 m²
Formula: 1 B4 = 2 × B5 (in area). So, if you have 1 B4 sheet, you can print 2 B5 pages from it (or fold it in half to create a B5 booklet).
📊 Quick Conversion Table: B4 to B5
| B4 Sheets | B5 Equivalent | Scale factor (side) | Real‑world use |
|---|---|---|---|
| 0.5 B4 | 1 B5 | 100% (B5 = half B4) | Single notebook page |
| 1 B4 | 2 B5 | 70.7% (reduce) | Magazine spread |
| 2 B4 | 4 B5 | 50% (half width/height) | Book section |
| 5 B4 | 10 B5 | 31.6% | Book chapter |
| 10 B4 | 20 B5 | 22.4% | Small book |
| 25 B4 | 50 B5 | 14.1% | Large book |
| 50 B4 | 100 B5 | 10% | Publication volume |
| 100 B4 | 200 B5 | 7.1% | Large catalog |
🖨️ Real‑World Examples: B4 to B5 in Action
- 📖 Magazine Publishing: B4 is commonly used for magazine spreads and large-format publications. When you need to produce B5 handouts or smaller versions, this converter tells you exactly how many B5 pages fit into a B4 layout.
- 📚 Book Production: B4 is used for book signatures and large-format books. B5 is used for notebooks and smaller publications. Understanding the scaling helps with production planning.
- 📓 Notebook Design: B5 is the classic notebook size. When designing from a B4 template, this converter helps you scale down for practical use.
- 🎨 Art & Photography: B4 prints are popular for medium-format art pieces. B5 offers a smaller format for portfolios and catalogs.
- 📬 Marketing Materials: B4 is used for large brochures and folders. B5 is used for handouts and business materials.
💡 Professional Tips for B4 to B5 Scaling
🎯 Resolution & Quality
When scaling from B4 to B5, if your original is 300 DPI, the resulting B5 will be ~424 DPI — actually higher quality! This is because you're concentrating the same pixels into a smaller area.
📐 B‑Series vs. A‑Series
B-series sizes are larger than A-series sizes at the same number. For example, B4 (250 × 353 mm) is larger than A4 (210 × 297 mm). Use B-series when you need more space than A-series offers.
💰 Printing Efficiency
Printing 2 B5 pages from 1 B4 sheet can save paper and costs. Many professional printers support B-series paper sizes — check your printer settings.
📂 Book Production
B4 is a common size for book signatures. When planning a book, understanding how B4 converts to B5 helps with production planning and paper selection.
❓ Frequently Asked Questions (B4 to B5)
Q: How many B5 sheets equal 1 B4?
A: Exactly 2 B5 sheets make 1 B4 in terms of area. You can fit two B5 pages on one B4 sheet.
Q: What is the scaling factor from B4 to B5?
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 B4 document onto a B5 sheet?
A: Yes, by scaling it down to 70.7% on each dimension. The document will fit, but text will be smaller.
Q: What is the difference in area between B4 and B5?
A: B4 has exactly double the area of B5 (0.08825 m² vs. 0.044 m²).
Q: Is B4 bigger than B5?
A: Yes, B4 is larger. B4 is the next size up from B5. 1 B4 = 2 × B5.
Q: What is B4 used for?
A: B4 is used for magazines, large books, professional printing, and publication design.
Q: What is B5 used for?
A: B5 is used for notebooks, journals, pocketbooks, and smaller publications.
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 is between A4 and A3 in size.
📈 Why Accurate B4‑to‑B5 Conversion Matters
Accurate scaling between B4 and B5 is essential for professional printing, book production, and document management. Whether you're preparing a magazine, designing a notebook, or planning a publication, 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 design. 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
- B3 = 353 × 500 mm – posters, book 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.