Catalogs can differ in the information they provide. Some of the common features include:
- Catalog Number: Most catalogs identify the stamps by using a numbering system for convenience. One of the best known is the Scott system.
- Catalog Value: Prices for individual stamps. While these prices do not always match the prices found on the open market, they do reflect overall trends in value changes. These prices will usually be for mint and used, but often include the values for FDCs and Plate Blocks.
- Picture: Stamp images are normally included but the number of images may vary.
- Identifiers: Tools for identifying issues that might otherwise be confusing due to numerous similar issues with varying minor details.
- Statistics: These include the date and location of issue, number of stamps issued, and the type of printing process used.
- Supplemental Information: This consists of extra information about specific stamps or stamp series that will be of use to the philatelist in organizing their collection and gaining a deeper understanding of the material.
Some of the more well known catalogs include: Scott, Minkus, Michel, Stanley Gibbons, H.E. Harris, and Yvert et Tellier. Many postal authorities issue their own catalogs as well. Older catalogs are often very useful in working with older issues (which often had more variations), providing more detailed information in some cases. Catalogs are migrating to electronic formats, whether as standalone software, PDFs or web-based resources.