B-Series Paper Size Calculator
Select an ISO B-series paper size to see its dimensions in millimeters, centimeters, and inches, plus area, perimeter, diagonal, and sheet relationships.
Last updated: July 2026
ISO B-series dimensions
ISO B-series relationship
ISO B0 through B10 reference table
| Size | Millimeters | Centimeters | Inches |
|---|---|---|---|
| B0 | 1000 × 1414 mm | 100 × 141.4 cm | 39.3701 × 55.6693 in |
| B1 | 707 × 1000 mm | 70.7 × 100 cm | 27.8346 × 39.3701 in |
| B2 | 500 × 707 mm | 50 × 70.7 cm | 19.685 × 27.8346 in |
| B3 | 353 × 500 mm | 35.3 × 50 cm | 13.8976 × 19.685 in |
| B4 | 250 × 353 mm | 25 × 35.3 cm | 9.8425 × 13.8976 in |
| B5 | 176 × 250 mm | 17.6 × 25 cm | 6.9291 × 9.8425 in |
| B6 | 125 × 176 mm | 12.5 × 17.6 cm | 4.9213 × 6.9291 in |
| B7 | 88 × 125 mm | 8.8 × 12.5 cm | 3.4646 × 4.9213 in |
| B8 | 62 × 88 mm | 6.2 × 8.8 cm | 2.4409 × 3.4646 in |
| B9 | 44 × 62 mm | 4.4 × 6.2 cm | 1.7323 × 2.4409 in |
| B10 | 31 × 44 mm | 3.1 × 4.4 cm | 1.2205 × 1.7323 in |
What this ISO B-series paper calculator tells you
Select ISO B0 through B10 to see fixed dimensions in millimeters and conversions to centimeters and inches. The calculator also reports area, perimeter, diagonal, combined one-face area for multiple sheets, and nominal parent and child relationships.
ISO B0 through B10 dimensions
The reference table uses fixed, published whole-millimeter dimensions as the source of truth. Each physical calculation begins with those values rather than recursively halving B0, preventing cumulative rounding errors.
How B-series sizes are related
Successive ISO B sizes are nominally produced by halving the preceding sheet parallel to its shorter side. A size Bn corresponds to 2n nominal sheets per B0 and n successive halvings. The nominal relationship explains sheet hierarchy; physical area is always calculated from the fixed rounded dimensions.
ISO B-series versus A-series paper
ISO A and B sheets share approximately the same √2 proportions. A B size is generally positioned between neighboring A sizes, which can make it useful when an intermediate sheet is needed. Similarly numbered sizes are not interchangeable: for example, B4 is larger than A4. Use the related A-Series Paper Size Calculator for A0 through A10.
Why the ISO standard must be specified
This calculator uses the ISO B-series dimensions. Some regional paper systems use different dimensions under similar B-series names. Confirm ISO B-series compatibility with the printer, print shop, document specification, or paper supplier before printing or ordering.
Portrait versus landscape orientation
Portrait uses the shorter side as width and the longer side as height. Landscape swaps those dimensions. Orientation does not change area, perimeter, diagonal, quantity totals, or the nominal B-series relationships.
How area, perimeter, and diagonal are calculated
Area is width multiplied by height, perimeter is twice the sum of width and height, and diagonal uses the Pythagorean relationship. Sheet quantity multiplies only the area of one face—not dimensions, perimeter, diagonal, or a two-sided surface area.
Why rounded dimensions differ slightly from theory
The theoretical ISO A- and B-series aspect ratio is √2:1, and successive sheets retain approximately those proportions. Published dimensions are rounded to whole millimeters, so ratios and areas calculated from the fixed sizes can differ slightly from theoretical geometry.
Worked examples
B4 portrait
ISO B4 is 250 × 353 mm, 25 × 35.3 cm, or approximately 9.8425197 × 13.8976378 inches. Its area is 88,250 mm² or 0.08825 m², perimeter is 1,206 mm, and diagonal is approximately 432.5609784 mm. B4 has 16 nominal sheets per B0, four halvings, parent B3, and child B5.
Ten B3 landscape sheets
B3 landscape is 500 × 353 mm. Each sheet has an area of 176,500 mm², so ten have 1,765,000 mm² or 1.765 m² of combined one-face area. Perimeter is 1,706 mm, diagonal is approximately 612.0531023 mm, and B3 has eight nominal sheets per B0.
B0 portrait
B0 is 1,000 × 1,414 mm. Its fixed rounded dimensions give an area of 1,414,000 mm² or 1.414 m², a perimeter of 4,828 mm, and a diagonal of approximately 1,731.876439 mm. It has no supported parent, zero halvings, and child B1.
One hundred B5 sheets
B5 is 176 × 250 mm and has an area of 44,000 mm² per sheet. One hundred sheets have a combined one-face area of 4,400,000 mm² or 4.4 m². B5 has parent B4, child B6, and 32 nominal sheets per B0.
Frequently asked questions
What size is ISO B4 paper?
ISO B4 measures 250 × 353 mm in portrait orientation.
What are B5 dimensions in inches?
ISO B5 is approximately 6.9291 × 9.8425 inches.
What is the largest ISO B-series size?
B0 is the largest size supported here, at 1,000 × 1,414 mm.
How are B-series paper sizes calculated?
Successive sizes nominally halve the preceding sheet. This calculator uses the fixed whole-millimeter ISO dimensions rather than deriving them recursively.
Is B4 larger than A4?
Yes. ISO B4 is 250 × 353 mm, while A4 is 210 × 297 mm.
Is B5 the same as A5?
No. They share similar proportions but have different physical dimensions.
How many B4 sheets correspond to one B0 sheet?
The nominal relationship is 16 B4 sheets per B0.
Why does B0 have an area of approximately 1.414 square meters?
ISO B0 is based on √2 square meters in theory. Its rounded 1,000 × 1,414 mm dimensions calculate to 1.414 m².
Does landscape orientation change the paper area?
No. It only swaps width and height.
Why should I specify ISO B-series?
Other regional systems can use different dimensions for similarly named B paper.
Are all paper sizes called B4 identical?
No. Confirm the applicable standard rather than relying on the B4 name alone.
Does this calculator include printer margins?
No. Printable areas depend on the printer, paper handling, and settings.
Can it calculate pixels or DPI?
No. Pixel requirements depend on the intended print DPI; use the related image-print tools.
Can it calculate paper weight from GSM?
No. Paper weight requires GSM, sheet area, and quantity and is outside this calculator.