Callaghan, 33, was sentenced at the High Court at Auckland this morning to life in prison with a minimum non-parole period of 13 years and eight months.
The court heard he had smashed Thomas over the head at least eight times with a child's baseball bat, fracturing her skull.
A statement issued by Thomas' mother, stepfather and sister said they were satisfied with the actions of police and the New Zealand justice system.
Teresa, Wayne and Storm Scott said the sentence was a milestone.
"We thank God that we have reached this point today but acknowledge that nothing can ever bring Carmen back to us and for that, we are angry.
"We want to express our sincere gratitude and thanks to the police who acted professionally and compassionately throughout the search for Carmen and over the ensuing several months.
"We are grateful to see that the New Zealand justice system works the way it does and that Carmen's killer will be out of circulation for a long time so that he might be able to reflect on the immense damage he has done to so many more lives than he can ever imagine.''
The Carmen Thomas case
2010
June 27: Last confirmed sighting of Carmen Thomas, at Greenlane Countdown about 7.10pm. Last day her bank accounts were touched
June 28: Message sent from her Facebook account at 8.14pm
July 1: Police start seeking CCTV images from central Auckland
July 3: Text sent from Ms Thomas' phone to her boss at a Pakuranga men's club
July 7 or 8: Her car believed to be driven from Auckland to Hamilton
July 13: Car towed and Thomas reported missing
Sept 1: Ms Thomas' wheelie bin found by police
Sept 20: Police put a camera down a hole at a worksite on Victoria St in central Auckland
Sept 21: Ms Thomas' ex-partner Brad Callaghan charged with her murder. Police begin searching Callaghan's home
Sept 23: Police begin searching an East Auckland property where one of Callaghan's friends lives. They seize a boat, believed to have been used in a failed attempt to dispose of Ms Thomas' body, for forensic testing
Sept 24-26: Police stop searching Callaghan's Remuera house and the East Auckland home of an associate
Sept 27: Callaghan's fiancee Tanith Butler gives birth to his new son
Sept 27-28: Police receive information that Ms Thomas is buried at a site in the Waitakere Ranges. ESR scientists map out the area and begin searching
Oct 1: Concrete containers holding at least some parts of Ms Thomas are excavated and the find is announced at a hastily called press conference
Oct 2: Police continue searching the site and expect a post-mortem examination will be carried out
2011
May 25: Callaghan pleads not guilty to murder at the High Court at Auckland
July 15: Court documents show police say Callaghan killed Ms Thomas with multiple blows to the head
Sept 17: Callaghan denied bail at the High Court in Auckland
Oct 13: Ms Thomas farewelled by family and friends at a service in Auckland
Nov 25: Callaghan pleads guilty to the murder of Ms Thomas
2012
Mar 30: Callaghan jailed 13 years and eight months for murdering Carmen Thomas.
