Kalmer was born in the Roodepoort area of Johannesburg. Her first international medals came at the 1997 African Junior Athletics Championships, where she was the bronze medallist in both the 1500 m and 3000 metres events. As a junior runner she competed at the 1998 World Junior Championships in Athletics and at the World Cross Country event from 1996 to 1999. Her first senior international appearances followed two years later: she came 30th in the short race at the 2001 IAAF World Cross Country Championships and ran in the 1500 m heats at the 2001 World Championships in Athletics. She also finished eleventh in 5000 metres at the 2001 Summer Universiade. She was the silver medallist at the FISU World University Cross Country Championships in 2002, finishing behind Denisa Costescu. Over 5000 m she was eighth at the 2003 Summer Universiade, ninth at the 2007 All-Africa Games and sixth at the 2008 African Championships.