The true value of an antique is negotiated between a seller and buyer at the time of a sale. Determining the value of antiques takes extensive research and patience, and there is no easy or definite way to determine an antique's final selling price.
A good way to begin the valuation process is logging onto large web-based antique malls such as TIAS.com or RubyLane.com, and searching inventory for comparable items. Another way to get started is to contact a professional appraiser, although it is important to keep in mind that even with an written appraisal from a professional, there is no guarantee an antique is going to sell for its appraised price.
Ideally, professionals determine the appraised price of antiques by comparing the values to past recorded sales of identical or very similar items. Live auction results, many of which can be found online, are often used by professional appraisers. They typically throw out the highest and lowest figures and then average the remaining values.
Unfortunately, appraisers are often lucky to find one item that is identical to the antique they are researching, let alone several. Another factor that makes comparing prices difficult is the condition of the antique. Appraisers are often forced to branch out and make comparisons to similar items, or identical items of differing condition, in order to determine value.