Shane Clarke, 52, stabbed his partner Joanne Bishop 28 times with a screwdriver in a “frenzied attack” on 29 May, leaving her with multiple wounds to the chest and back.
On Friday, he was jailed for life for her murder at Oxford Crown Court, Thames Valley Police (TVP) said.
During a call to the emergency services, Clarke told a shocked female 999 operator: “I’ve just stabbed the missus.”
Speaking through hysterical laughter, he added: “I think she’s gone. I think she’s dead mate.”
When the operator asked him to return to the premises where he left Ms Bishop for dead, he said: “No, I don’t want to go back there.”
He also refused to check Ms Bishop’s condition after the operator asked if she was bleeding.
Ms Bishop was showing signs of life when paramedics arrived at the property in Brent, Tinkers Bridge, in Milton Keynes.
But she died four days later after medics worked “tirelessly” to save her.
Following the hearing, senior investigating officer Detective Inspector Stuart Blaik described Clarke’s 999 call as “horrific”.
He said: “Shane Clarke stabbed his partner Joanne Bishop in the torso and back with a screwdriver 28 times in a frenzied attack inside her home on the morning of Tuesday 29 May this year.
“Clarke callously left the address and sometime later called the South Central Ambulance Service.
“Clarke’s telephone conversation with the ambulance operator was horrific. He displayed no remorse or care for what he had done,” Mr Blaik added.