Stamps can vary significantly in their size depending on the type of stamp, the design, the stamps country of origin and the class of the stamp.
Forever Stamp Sizes
Forever stamps are the most common type of stamps used in the U.S.
The average first-class Forever stamp measures around 22mm x 25mm (0.87″ x 0.979″).
However forever stamps can vary in size depending on the design as the dimensions may need to be adjusted to better accommodate new designs.
Commemorative Forever Stamp Sizes
Commemorative forever stamps vary in size. This is because the dimensions are often adjusted to accommodate the different artwork on them.

For example:
- The Garden Beauty commemorative forever stamps which celebrate the American passion for flowers and gardens measure 20.22mm (W) x 23.11mm (H) or 1.19″ x 0.91″.
- The Brush Rabbit Additional Ounce Stamp measures 22.09mm (W) x 24.89mm (H) or 0.87″ x 0.98″.
- The Drug Free USA forever stamp measures 24.89mm (W) x 39.62mm (H) or 0.98″ x 1.56″. This stamp is far bigger than most forever stamps with a very long vertical size.
To find out the exact dimensions of any commemorative stamp follow these steps:
- go to the USPS website
- click the stamp you are interested in finding the dimensions of
- click ‘quick view’
- click ‘see full details’
- scroll down and select ‘product specs’ in the menu on the lower left
- the ‘overall size’ on this page will give you the total size of the stamp including perforations, the image area gives you the size of just the image on the stamp.
Royal Mail Stamp Sizes
In the UK the majority of Royal Mail stamps measure 21mm (W) x 24mm (H)/0.82″ x 0.94″.

This measurement is taken from the middle of the stamp perforation. In cases where the stamp is printed directly onto the envelope or packaging then the stamp will be 1.5mm narrower in both width and height due to the lack of a perforated edge. This gives printed Royal Mail stamps a size of 19.5mm (W) x 22.5mm (H)/0.77″ x 0.88″.