ISO 216 Standard

B-Series Paper Sizes

Complete B-series paper size reference: B0 through B10. Used for posters, large format prints, and specialty applications. Dimensions in millimeters, centimeters, and inches.

Complete B-Series Reference

Size Millimeters Centimeters Inches Common Use
B0 1000 × 1414 mm 100.0 × 141.4 cm 39.4 × 55.7 in Large posters, architectural drawings
B1 707 × 1000 mm 70.7 × 100.0 cm 27.8 × 39.4 in Posters, large format prints
B2 500 × 707 mm 50.0 × 70.7 cm 19.7 × 27.8 in Posters, wall charts
B3 353 × 500 mm 35.3 × 50.0 cm 13.9 × 19.7 in Small posters, newspapers
B4 250 × 353 mm 25.0 × 35.3 cm 9.8 × 13.9 in Books, magazines, envelopes
B5 176 × 250 mm 17.6 × 25.0 cm 6.9 × 9.8 in Books, passports, envelopes
B6 125 × 176 mm 12.5 × 17.6 cm 4.9 × 6.9 in Pocket books, notepads
B7 88 × 125 mm 8.8 × 12.5 cm 3.5 × 4.9 in Small notepads, passports
B8 62 × 88 mm 6.2 × 8.8 cm 2.4 × 3.5 in Playing cards, business cards
B9 44 × 62 mm 4.4 × 6.2 cm 1.7 × 2.4 in Small cards, tickets
B10 31 × 44 mm 3.1 × 4.4 cm 1.2 × 1.7 in Mini cards, stamps
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B-Series Relationship

B-series sizes are the geometric mean between A-series sizes. B4 is between A4 and A3, B5 is between A5 and A4, etc. Like A-series, folding a B-size in half gives you the next B-size (B4 folded = B5). B-series is less common than A-series but used for posters, books, and envelopes.

B-Series vs A-Series Comparison

A-Series Dimensions (mm) B-Series Dimensions (mm) Relationship
A4 210 × 297 B4 250 × 353 B4 is 19% larger than A4
A3 297 × 420 B4 250 × 353 B4 fits between A4 and A3
A5 148 × 210 B5 176 × 250 B5 is 19% larger than A5

Understanding B-Series Paper

What is B-Series?

B-series paper sizes are defined in ISO 216, the same standard as A-series. They provide intermediate sizes that fill gaps in the A-series scale.

The Mathematics

B-series sizes are calculated as:

  • B0: 1 meter × √2 meters (1000 × 1414 mm)
  • Each size: Half the area of the previous size
  • Aspect ratio: 1:√2 (same as A-series)

Common Uses

  • Posters: B0-B2 for large format printing
  • Books: B5 is popular book size in many countries
  • Envelopes: B4 and B5 envelopes fit A4 and A5 sheets
  • Passports: Often use B7 size (88 × 125 mm)

B-Series vs C-Series

While B-series provides intermediate paper sizes, C-series is used for envelopes:

  • C4 envelope fits A4 paper unfolded
  • C5 envelope fits A4 paper folded once (A5 size)
  • C6 envelope fits A4 paper folded twice (A6 size)