Calvin Howarth (born 18 June 1976 in Auckland, New Zealand) is a New Zealand born former Scotland 'A' international rugby union player. He plays at Fly-half. Howarth was selected for Scotland A on the basis of a four-year residency period and played in Scotland's match against Romania in 2002 to confirm his Scottish nationality. His older brother Shane Howarth represented both New Zealand and Wales. He stayed at Glasgow Warriors until 2006-07 season when he moved to Italian side Viadana and stayed there until 2009. Now back in Auckland, New Zealand, Howarth is a real estate consultant.