The smallest stamp in the world was issued by Bolivar in 1863. It was a mere 3/8″ x 1/2″
Bolivar is a State in the Confederation of States of Columbia, and each State could issue its own stamps. In 1883, Columbia became a republic and the States could no longer issue their own stamps.
The World’s Smallest Postal Stamp
The world’s smallest stamp is the Bolivar 10c green stamp. It is the smallest stamp issued for actual postal usage. The stamp is known for being only 8.00mm x 9.55mm. This stamp was issued in Bolivar, one of the nine states in the United States of Columbia, in 1863. This stamp features the coat of arms of Bolivar as shown in the figures below.
There are two versions of the of the stamp – the first being the green stamp (fig. 1) depicting 6 stars and another green stamp with 5 stars underneath the shield. The series also comprises of a rose hued stamp (fig. 2). The series is in the denominations of 10 centavos and 1 peso and are imperforated.
Design-wise the stamp doesn’t look particularly special. Its uniqueness comes from its size. As it’s no more than 8mm x 9.5mm in size, it is recognized as being exceptionally small. In comparison, a standard stamp is 22.10mm x 24.89mm. Figure 3. gives us an idea as to how small this stamp must be.
Source: The World’s Smallest Postal Stamp – The Royal College