Quick answer: The ISO B series runs from B0 at 1000 × 1414 mm to B10 at 31 × 44 mm. B sizes use the same 1:√2 proportion as A sizes and generally provide an intermediate choice between neighbouring A formats.
Measurement note: dimensions are stated width × height in portrait orientation. Turn the sheet through 90 degrees for landscape use. Millimetres are the controlling values for ISO sizes; inch figures are rounded conversions.
Complete B0 to B10 size chart
| Size | Millimetres | Centimetres | Inches |
|---|---|---|---|
| B0 | 1000 × 1414 mm | 100 × 141.4 cm | 39.37 × 55.67 in |
| B1 | 707 × 1000 mm | 70.7 × 100 cm | 27.83 × 39.37 in |
| B2 | 500 × 707 mm | 50 × 70.7 cm | 19.69 × 27.83 in |
| B3 | 353 × 500 mm | 35.3 × 50 cm | 13.90 × 19.69 in |
| B4 | 250 × 353 mm | 25 × 35.3 cm | 9.84 × 13.90 in |
| B5 | 176 × 250 mm | 17.6 × 25 cm | 6.93 × 9.84 in |
| B6 | 125 × 176 mm | 12.5 × 17.6 cm | 4.92 × 6.93 in |
| B7 | 88 × 125 mm | 8.8 × 12.5 cm | 3.46 × 4.92 in |
| B8 | 62 × 88 mm | 6.2 × 8.8 cm | 2.44 × 3.46 in |
| B9 | 44 × 62 mm | 4.4 × 6.2 cm | 1.73 × 2.44 in |
| B10 | 31 × 44 mm | 3.1 × 4.4 cm | 1.22 × 1.73 in |
How B sizes are defined
B0 has a short side of 1000 mm and a long side rounded to 1414 mm. Each following size is produced by halving the previous sheet. As with the A series, the shape remains constant when the sheet is halved and rotated.
Where B sizes are used
B formats are encountered in poster printing, books, art paper, maps, envelopes in some national systems and specialist stationery. Availability varies more than A4 or A3, so a designer should confirm stock and machine support before committing to a format.
- B0 and B1 for large display and production work
- B2 for posters, artwork and presentation graphics
- B3 and B4 for posters, books, drawings and premium printed pieces
- B5 and B6 for books, notebooks, journals and compact publications
- B7 to B10 for cards, labels and small-format uses
B sizes compared with A sizes
A B-series sheet is not simply an A sheet with an added margin. It has its own standard dimensions. B1, for example, is 707 × 1000 mm, which places it between A0 and A1 by linear size. The intermediate formats can reduce waste when an A size is too large but the next A size is too small.
Printing and purchasing
Desktop printer menus may list only a subset of B sizes, and Japanese JIS B sizes differ from ISO B sizes. When ordering paper or setting a file, specify both the designation and the millimetre dimensions. “B5” without the standard or measurements can be ambiguous in international workflows.
Frequently asked questions
Is B5 the same everywhere?
No. ISO B5 is 176 × 250 mm. JIS B5 is 182 × 257 mm. Confirm which system the printer, notebook or software uses.
Is B series covered by ISO 216?
Yes. ISO 216 specifies the trimmed A and B series.
What is the most useful B size?
That depends on the product. B2 is a practical poster size; B5 is common for books and notebooks; B0 and B1 suit large graphics.
Common mistakes to avoid
- Entering rounded inch conversions when exact millimetres are available.
- Confusing finished trim with bleed or parent-sheet dimensions.
- Allowing the printer driver to scale automatically.
- Assuming a named size is identical in every national standard.
- Ordering paper before checking the printer’s minimum, maximum and supported weight.
- Judging readability only on a zoomed computer display.
For B-Series Paper Sizes Explained, the most dependable approach is to retain the standard’s controlling unit, state the dimensions in the purchase order, use a supplier template and approve a full-size proof. This is especially important when the project moves between countries, software packages or production methods.
How to specify the size without ambiguity
For B-Series Paper Sizes Explained, a reliable print specification states more than the familiar format name. Give the finished width and height, measurement unit, orientation, number of pages or panels, paper weight, surface, colour process, bleed, finishing and quantity. This prevents regional names and printer defaults from silently changing this particular job.
- Finished size: write width × height and identify portrait or landscape.
- Artwork size: distinguish the trimmed page from any larger bleed canvas or parent sheet.
- Stock: specify grammage or basis weight, coating, colour and recycled or certified requirements.
- Finishing: state folds, scoring, binding, drilling, corner rounding, lamination or mounting.
- Tolerance: ask the supplier what cutting, folding and registration variation should be expected.
When ordering B-Series Paper Sizes Explained, a short name alone leaves important decisions unstated. A specification such as “finished size as stated above; portrait; 3 mm bleed; 170 gsm uncoated white stock; full colour both sides; scored where shown” is harder to misinterpret. When the format has regional variants, include the governing standard or exact dimensions every time.
Make a full-size physical proof
Screens do not communicate the physical scale of B-Series Paper Sizes Explained reliably. Before a large order, print a representative page at 100%, trim it to the stated size and use it as the finished item will be used. Measure one horizontal and one vertical feature with a ruler. Fold it, place it in its envelope or holder where relevant, view it from the intended distance and ask someone unfamiliar with the design to find the main information.
A proof of B-Series Paper Sizes Explained should check more than spelling. Look for text that is technically present but difficult to read, lines that sit too close to the trim, images whose important details enter a fold or binding area, barcodes or QR codes that do not scan, and stocks that crack or show through. For colour-critical work, a calibrated contract proof or press proof is more informative than an office print.
Sources and standards
The measurements and production guidance in this guide were checked against the following standards bodies, postal operators and print-platform specifications. Standards can be revised or withdrawn, so check the linked record when a contractual or regulated specification matters.