Foolscap

The standard British writing and office sheet, 17 by 13¾ inches, named after a watermark.

Foolscap was the sheet British offices ran on. Letters, ledgers, legal drafts and school exercise books were all cut from it, and foolscap folio — the sheet folded once — was the standard page of British paperwork until A4 arrived in the 1960s and quietly won.

The name is usually explained by the watermark: early Continental papermakers are said to have marked their sheets with a jester’s cap and bells, and the size took the name of the mark. It is the explanation everyone gives and we have not found it documented in a source we would cite, so take it as likely rather than established.

One curiosity worth noting. Where crown and demy double exactly — double crown is precisely twice crown — foolscap does not. A double foolscap at 27 by 17 inches is 459 square inches against a single sheet’s 233.75, which is 1.96 times rather than 2. The foolscap series was built by eye and convention rather than by arithmetic.