Calvin purchased a 40% partnership interest for $43,000 in February 2016. His share of partnership income in 2016 was $22,000, in 2017 was $25,000, and in 2018 was $12,000. He made no additional contributions to or withdrawals from the partnership. On December 18, 2018, Calvin sold his partnership interest for $103,000. What is his gain or loss on the sale of his partnership interest?