Instructions
Identify the flag. You may have a vague idea of where the flag comes from or in what period it was produced, but the more you know about the flag, the easier it will be to value. Check websites such as Flags of the World to find a list of flags from around the world. If the flag was passed down in your family, try asking your relatives. They might have some idea of the flag's origin.
Visit your local library to find books about flags. You may also be able to find some relevant books online. The World Flag Database has a list of books that may be useful. They may also have price guides, which can help you value antiques, and if you're lucky, your flag.
Bring your flag to a local antiques store to be identified and appraised. Keep in mind that not all antiques dealers are qualified to appraise antiques, so call ahead. Some dealers may not value or appraise your flag. Instead, the dealer may simply make you an offer for it. This can end up being lower or higher than the actual value of the flag.
Use an online appraisal service. What's This Worth has a list of online appraisal services. Consult various appraisal websites to ensure you find one that is suitable. You will need to pay a small fee and wait a few days, but you should get an accurate appraisal. If you are confident your flag is valuable, use an offline appraisal service such as Sotheby's.
Visit an antiques trade show. Some shows such as the Antiques Roadshow regularly tour the country and are a good way to get your flag seen by a professional.
Try getting your flag evaluated by a second expert. By getting your flag valued by two different sources, you ensure that you have an accurate idea of your flag's worth.