1 000 000 000 B.‑pengő

The B.-pengő — "bilpengő," shorthand for billió pengő, or one trillion pengő — was a unit invented purely to cope with the most severe hyperinflation ever recorded. By mid-1946, Hungary's daily inflation rate exceeded 200%, and the pengő had collapsed so completely that denominations in the hundreds of trillions became necessary for ordinary transactions. This note, face value one billion B.-pengő, represents 10²¹ original pengő — a number requiring scientific notation to write sensibly.

The stabilization came on 1 August 1946 with the introduction of the forint, at a conversion rate of 400,000 quadrillion pengő to one forint. Notes of this series were in official use for weeks, not months.