B5
B-Series (ISO 216) · 7 specs
Direct Answer
B5 is an ISO 216 standard paper size measuring 176 × 250 mm (6.93 × 9.84 inches). Sized perfectly between A4 and A5, it is the premier international standard for published books, university academic textbooks, scientific journals, and luxury stationery notebooks.
Source: ISO 216:2007 (DIN 476-1) · Last reviewed Aug 28, 2026
Specs
| Width × Height (Metric) | 176 × 250 mm |
| Width × Height (Imperial) | 6.93 × 9.84 in |
| Nominal Surface Area | 0.044 m² (44,000 mm²) |
| Geometric Mean Origin | Geometric mean of A4 (210×297 mm) and A5 (148×210 mm) |
| Japanese JIS B5 Distinction | JIS B5 (182 × 257 mm) is the dominant school notebook size in Japan |
| Weight of 80 gsm Sheet | 3.52 grams |
| Primary Applications | Scientific textbooks, academic research journals, luxury stationery (Leuchtturm B5), tablet computer screens |
The Premier Publishing Format
In commercial book publishing, standard A4 is too wide for comfortable single-column reading (requiring awkward double-column text blocks), while A5 can feel cramped for technical literature containing large equations, tables, and side margins. B5 (176 × 250 mm) is the industry's gold standard for academic monographs, engineering handbooks, and university coursebooks.
Digital Tablet Aspect Ratios
Many modern e-readers and digital paper tablets (such as the reMarkable 2, Supernote A5 X, and iPad Air) design their display active areas around the B5 physical aspect ratio to emulate physical notebook page layout.