Before ISO 216 became the international standard, Britain had its own rich tradition of paper sizes, many of them still remembered in bookbinding and historic printing.
Foolscap: The Everyday Size
Foolscap (203 × 330 mm, or roughly 8 × 13 inches) was the standard British writing paper for centuries. Its name comes from the watermark of a jester's cap ("fool's cap") used by Elizabethan papermakers. It was the paper of letters, legal documents, and school exercise books. When ISO A4 arrived in the 1970s, Foolscap gradually faded — but it is still referenced in older documents.
Quarto, Folio, Octavo: The Book Folding Names
These come from the number of times the original sheet is folded:
- Folio — one fold (2 leaves, 4 pages). Largest; used for deluxe editions.
- Quarto — two folds (4 leaves, 8 pages). Common for scholarly books and reference works.
- Octavo — three folds (8 leaves, 16 pages). The standard book size for centuries.
- Duodecimo (12mo) — twelve leaves per sheet. Pocket books.
- Sextodecimo (16mo) — sixteen leaves. Small books.
These terms survive in the antiquarian book trade and library cataloguing.
Imperial: The Grand Sizes
The "imperial" family of sizes is the largest of the traditional British formats:
- Imperial — 22 × 30 in (559 × 762 mm)
- Royal — 20 × 25 in (508 × 635 mm)
- Demy — 17.5 × 22.5 in (445 × 572 mm)
- Crown — 15 × 20 in (381 × 508 mm)
- Elephant — 23 × 28 in (584 × 711 mm)
- Double Elephant — 26.75 × 40 in (678 × 1016 mm)
- Atlas — 26 × 34 in (660 × 864 mm)
- Emperor — 48 × 72 in (1219 × 1829 mm)
Newspaper and Poster Sizes
Many "broadsheet" newspapers used a page size close to the traditional "Royal" or "Imperial". The famous The Times of London was printed on paper 24 × 36 inches. Today, most British newspapers have moved to the smaller "compact" or "Berliner" format.
Why This Matters Today
If you are restoring a historic book or trying to reproduce an antique print, you need to match the original paper size. Likewise, if you are buying a "foolscap" folder or "imperial" drawing board, you are using a term that has been in continuous use since the 1600s.
Our database lists every traditional British size, including regional variants (Kings, Dukes, Pott, Brief, and more).