Sangakkara, who has made scores of 105 not out, 117 not out and 104 in his last three World Cup matches, believes it is the right time to step away from the game.
"There are Test matches in June and July, and I will be done by the end of August. A series or two in June and in August, and that's it," Sangakkara, who will quit ODIs after the ongoing World Cup, said on Sunday.
Despite being at a loss of words to explain his recent form, Sangakkara made it clear that his performances with the bat will not matter unless Sri Lanka start winning more matches.
"I don't know whether I am top of my game, I just bat according to situations," he said. "During the [preceding] New Zealand tour, it was the same thing, I didn't have a good start in the first ODI but from the second onwards it was just a case of building on runs.
"[For the team] it has gone pretty well up to now. Again a slow start, a bit shaky against Afghanistan, but pretty good in the last two games. It's just a case of trying to ensure that we put up a good performance every time we go out and keep on improving."
Joining Sangakkara into ODI retirement is long-time friend and team-mate Mahela Jayawardene.
Both players have been the anchor of Sri Lanka's middle order for nearly a decade now. But, with the duo hanging up their boots at the same time, Sri Lanka will have to act fast in order to plug the massive hole that will be left behind by them.
While choosing Sangakkara and Jayawardene's successors will be no easy task for the national selectors, Sanagakkara has already pinpointed two batsmen who he be believes are the right candidates.
One is batsman Lahiru Thirimanne, who is capable of batting at any position on the batting order and recently scored a career-best 139 not out against England.
The other is wicketkeeper-batsman Dinesh Chandimal, who has been a lot more inconsistent despite showing flashes of brilliance.
Speaking about why he picked Thirimanne and Chandimal, Sangakkara said: "He [Thirimanne] batted beautifully and fought through some tough situations. He's done a lot of hard work for the team and seems to be very impressive.
"Thiri is much better than where I was when I was his age, I think he can only get better and that's really exciting for us."
Despite having been in and out of the national team throughout his international career, Sangakkara has backed Chandimal to come good.
"Unfortunately he's not had some good outings here," Sangakkara said. "He batted really well in the last two games against England in Sri Lanka, came here and unfortunately was not in the side for the first three-four New Zealand games. Since then it's been a tough comeback for him.
"He's batting well, he is a great player, really positive. He's got everything to make him a really good player for Sri Lanka. I hope he keeps getting the opportunity and when he does, keeps doing what's required of him.
"Technique or anything else, it's about scoring runs. Chandi has shown he has the ability to score runs especially against good attacks. Coming in the second Test at Wellington and batting at 85 for 5 and getting 70-odd was another tough knock under pressure. He has the ability to do that, he just needs be free and happy and keep getting opportunities."