Fiqh-us-Sunnah Volume 5, Hajj and ‘Umrah, Fiqh 5.073A.
Section : One Must Complete Seven Rounds of the Ka’bah.
Thus, if one leaves even a single step in any of the seven rounds that round will not be counted. If one is doubtful as to the number of rounds performed, one must assume the least number of rounds, and then complete the seven rounds. In cases where one completes a Tawaf and then finds oneself not so sure about the number of rounds performed, one incurs no penalty nor is required to do anything.