You'd think the carefree days of childhood would rank as most people's happiest.
But in fact men are happiest at 40 while women are most content at 38 when they are fit and healthy and have good friends.
A survey revealed that the best moments in life are the birth of a first child, your wedding day and the birth of grandchildren.
The findings, from a poll of 1,000 people aged 70 and over by the insurance firm Beagle Street, show that loving relationships are more important than money or material gain.
The most common regrets were choosing the wrong career and not pursuing lifelong dreams.
The research involved quizzing 1,000 'life experts' aged 70 or older who have the benefit of life experience and hindsight. They were asked about their happiest moments and their biggest regrets in life.
Other happiest moments to make the top ten included the day you retire, moving into a new home, seeing your child's first steps and meeting the man or woman of your dreams.
The research was carried out by online insurance company Beagle Street to mark the release of a new short film called Happiest Moment, featuring some of the UK's oldest couples passing on advice to the younger generation.
More than half the people questioned said they had no regrets in life, but for those that did the most common regret was choosing the wrong career and not pursuing lifelong dreams.
One in ten of those with regrets wished they had worked harder in school and seven per cent regretted not travelling the world more.
The other two to make the top five were getting divorced and getting married too soon.
The top piece if advice the pensioners could pass on to younger generations was to never take the people you love for granted.
Other top pearls of wisdom were 'believe in yourself', 'nothing worth having comes easy' and 'don't hold grudges'.
Matthew Gledhill, managing director of Beagle Street, said: 'The overwhelming message from those with the most life experience is that the key to happiness is to worry less and live in the moment with the people you care about most.
'We commissioned Happiest Moment because we want our customers to be happy as it is scientifically proven that happier people live longer.“
'As much as people look to the future and try to climb career ladders, the film and our research clearly show that happiness is linked much more heavily to relationships, friends and family than societal or monetary status.'