Evaluating physicians may need to account for the effects of multiple impairments using a summary value. In the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition, the Combined Values Chart provides a method to combine two or more impairment percentages based on the formula A + B(1 – A) = the combined value of A and B. Using the Combined Values Chart and this formula, physicians can combine multiple impairments so that the whole person impairment is equal to or less than the sum of all the individual impairment values. The AMA Guides, Sixth Edition, specifies that “impairments are successively combined by first combining the largest number with the next largest remaining number, and then further combining it with the next largest remaining number … until all given impairment numbers are combined.” Impairment values within a region generally are combined and converted to whole person permanent impairment before being combined with values from other regions. The article reviews the AMA Guides, Sixth Edition, approach to combining upper extremity impairments, lower extremity impairments, and combining spinal impairments.