Domestic abuse in the Thames Valley costs the public £200m a year, a police authority has estimated.
The costs were revealed as part of a Thames Valley Police Authority campaign to raise awareness of the crime.
Authority chairman Khan Juna said costs came from the "impact on the criminal justice system, child social care, housing, employment and health care".
The Speak Out Today campaign is being launched with domestic abuse co-ordinators and Crimestoppers.
An authority spokesman said the majority of domestic abuse "still goes unreported", and the focus of the campaign is to encourage people to contact either the police, Crimestoppers or specialist support agencies.
The campaign comes with a website launched to provide information for victims and those supporting them.
Liz Jones, domestic and sexual Abuse co-ordinator at Oxford City Council said: "We need people to come forward before it is too late.
"We should not put the onus of responsibility purely on the victims to speak out."