It is not having lots of money that makes us happy - it is spending it on others, Canadian researchers suggest.
Best not to keep it all
A team from the University of British Columbia said spending as little as $5 (£2.52) on others helped.
Staff who got bonuses and spent some of the extra money on others were happier than those who spent their bonuses on themselves, the research found.
A UK psychologist said such charitable giving improved how people saw themselves - and how others saw them.
Route to happiness?
The research was published in the 21 March edition of the publication Science.
The researchers first carried out a survey of 630 people which asked them to rate their general happiness, report their annual income; and provide a breakdown of their monthly spending including bills, gifts for themselves, gifts for others and donations to charity.
Professor Elizabeth Dunn, who led the research, said: "We wanted to test our theory that how people spend their money is at least as important as how much money they earn."
"Regardless of how much income each person made, those who spent money on others reported greater happiness, while those who spent more on themselves did not."
The team then assessed the happiness of 16 employees at a firm in Boston, both before and after they received their profit-sharing bonus, which ranged between $3,000 (£1,514) and $8,000 (£4,039).
It appeared it was not the size of the bonus that mattered, but what the employees spent it on.
Those who gave more of their bonus as gifts to others, or to charity, consistently reported greater benefits than employees who simply spent money on their own needs.
In another experiment, the researchers gave 46 people $5 or $20, asking them to spend the money by five that afternoon.
Half the participants were instructed to spend the money on themselves, and half were assigned to spend the money on others.
'Seen as altruist'
Those who spent the cash on others reported feeling happier at the end of the day than those who spent the money on themselves, no matter how much they had been given.
Dr Dunn said: "This study provides initial evidence that how people spend their money may be as important for their happiness as how much money they earn.
"And spending money on others might represent a more effective route to happiness than spending money on oneself."
Dr George Fieldman, a psychologist at Buckinghamshire New University, said: "Giving to charity partly makes you feel better because you're in a group. You are also perceived as being an altruist.
"On an individual level, if I give to you, you are less likely to attack me and more likely to be nice to me."