Stefano Brizzi, from south London, admitted dismembering Gordon Semple, 59, when he was high on crystal meth.
The Italian national claimed PC Semple, who he met on dating app Grindr, died accidentally during a sex game.
Jurors at the Old Bailey convicted the 50-year-old on a 10-2 majority after five days of deliberations.
He had already pleaded guilty to obstructing the coroner. He will be sentenced on 9 December.
The former Morgan Stanley IT developer claimed Mr Semple, from Greenhithe in Kent, had died on 1 April during a "sex game gone wrong" when a dog leash he was wearing had slipped.
However, the court heard it would have taken far longer for him to be strangled than Brizzi's account suggested.
In the days after the killing, he was filmed on CCTV buying buckets, a perforated metal sheet and cleaning products from a DIY store. He then started to dismember the body and strip the flesh.
Six days after his death, police officers found PC Semple's partially-dissolved body parts in the bath when they visited Brizzi's flat to investigate reports of a putrid smell emanating from his home.
Killing highlights dark world of hook-up apps
The court heard Brizzi was obsessed with the American TV show Breaking Bad in which the protagonists Walter White and Jesse Pinkman dissolve a rival drug dealer in a bathtub filled with acid.
When police visited Brizzi's flat on the Peabody Estate in south London, he told them how he thought he was "getting away with it" and was planning to finish disposing of the body later that day.
The court was played a video of a police interview in which Brizzi can be heard saying: "As you can see this man was a very big man and all I have left is two buckets."
Police found "globules" of flesh floating in the bath, bags containing bones and a part of PC Semple's head, and pools of human fat in the oven.
The court heard there was evidence in the kitchen that Brizzi had chopped up the Inverness-born officer with a variety of utensils and may have even used chopsticks to eat morsels of cooked meat.
Following his arrest, Brizzi admitted trying to dissolve the body of a policeman because "Satan told me to".
Brizzi told jurors PC Semple died in a "state of erotic bliss".
He also told police he had "chucked" some of PC Semple's body into the Thames and thrown away his police badge and belongings.
A human foot was later found by a member of Thames Mudlark Club near Bermondsey Wall.
In a statement, PC Semple's family said: "Gordon was a loyal and much loved long-term partner, brother, brother-in-law, uncle, cousin and friend to all.
"We were devastated when the news broke of Gordon's murder and the circumstances, which are still incredibly hard to deal with. It is still insurmountably upsetting."
Malcolm McHaffie, deputy chief crown prosecutor for CPS London, said Brizzi was an "evil and calculating man".
"He cynically lied to the court and the jury, claiming that PC Semple's tragic death was caused when a sex game went horribly wrong and that he had taken drugs which caused him to try to cover up the death. This was all fabricated by Brizzi to evade justice."
He said it had been "challenging" to piece together what had happened because of the extreme lengths Brizzi had gone to cover up his crimes.
Det Ch Supt Peter Ayling said Brizzi went to "sickening lengths" to dispose of PC Semple's remains, which amounted to cannibalism.
"Brizzi clearly and coldly laid a false trail by contacting Gordon on Grindr five days after he himself had murdered him and weaving a fictitious account of what took place that afternoon.
"Brizzi was unaware that Gordon was a police officer and the investigation has proved that the two men had never met before. Only Brizzi will know the reasons why that day he became a killer."
He said the men had both routinely used Grindr to meet men for sex and drug use.
"Sadly, it is clear from the investigation that Gordon, a man who had dedicated the last three decades of his life to policing London, was behaving on duty in a way that no police officer should. Gordon held a position of trust, and he broke that trust.
"However, nothing should distract from the actions of Stefano Brizzi and the blame for Gordon's death lies firmly with this man, a killer whose cold calculated actions are so grotesque they are beyond comprehension."
A man who strangled a Met Police officer before trying to dissolve his body in an acid-filled bath has been found guilty of murder.