What Is A Coil Pair Of Stamps

Coil stamps are often collected as attached pairs.

The U.S. Postal Service sells stamps in different formats to meet the needs of different users. In addition to the familiar sheets of stamps, the U.S. Postal Service offers strips of stamps rolled up into coils of 50 to 10,000 stamps to meet the needs of mass mailers and vending machine operators, but anyone can buy them. Foreign postal administrations also issue stamps in the coil format. United States stamps are produced to Postal Service order by the U.S. Bureau of Engraving and Printing in Washington, D.C.

What’s A Coil Pair?

Coil stamps have two parallel smooth edges and two parallel perforated edges. The design can be oriented either horizontally or vertically. A coil pair is simply two coil stamps that have not been separated. According to “Linn’s Stamp News,” some stamp collectors prefer their coil stamps in pairs to better display their distinctive smooth edges. In addition to traditional water-activated adhesive stamps, the Postal Service also issues self-sticking coil stamps with two smooth edges and two die-cut edges that simulate perforations, or with smooth edges all around. These also are collected in pairs.


Coil stamps date back to October 1906 when the U.S. Post Office Department, forerunner of the U.S. Postal Service, began selling sheets of stamps without perforations that private companies would slice into strips, then perforate and paste together into coils. According to Linn’s, the Post Office Department began selling its own coil stamps in 1908 and in 1927 stopped selling the non-perforated sheets to private coil makers. Great Britain was the second nation to issue coil stamps–in 1912. Other countries followed.

Coil Line Pairs

There’s a coil pair variety that’s distinguished by a thin printed line between the two stamps. Collectors call these line pairs and may pay a premium for them because they occur infrequently. The line occurs when ink collects in the joint between sections of the printing plates, and prints a line on the white space between stamps.

Plate Number Coils

The Postal Service in 1981 inadvertently created another major coil variety when it ordered that printing plate numbers be printed on the coil stamps for improved quality control, rather than putting plate numbers on the printing selvage that gets trimmed off. Collectors of these plate number coils, or PNCs, collect them in mint strips of three or five stamps with the stamp bearing the plate number in the center, or as used single stamps. The Plate Number Coil Collectors’ Club says a plate number typically occurs once per 52 coil stamps but can also occur more frequently depending on the stamp design. The club says coil plate numbers are found in the margin below the stamp design.

Other Ways to Collect Coils

Coil stamps offer other options for collectors, according to Linn’s. Some collectors specialize in the private stamp-coil makers operating in the U.S. from 1906 to 1927, each of whom used distinctive perforations that differed by number, size and pattern. Other collectors specialize in the coil issues and coil varieties from Britain, Sweden, Germany and other countries.