A healthy amount of sleep has a far higher impact on wellbeing than a 50% increase in disposable income, a study of Britons' quality of life has found.
There is a significant gap between those who are living the best and worst in Britain, with sleep quality found to be the strongest indicator of living well, the study by Oxford Economics and the National Centre for Social Research for Sainsbury's found.
Those who are satisfied with their sex lives, have job security and a connection with their community are also disproportionately likely to rank at the top of the inaugural Living Well Index.
Researchers found the average Briton has a "living well score" of 62.2 out of 100, with those living the best defined as the 20% of the population with the highest scores, falling between 72 and 92.
They found income has surprisingly little impact on how people feel, with a 50% rise in income contributing to just a 0.5 point increase in a typical Briton's overall score, while sleep quality could explain 3.8 points of difference between a typical person's score and those in the top 20%.
Worrying about the health of close relations contributed to a difference of 1.75 points between the typical Briton and those living best.
Researchers asked a nationally representative panel of 8,250 people questions about 60 different aspects of their behaviour, how they live and how they feel.
The same panel will be questioned every six months, enabling the supermarket and researchers to track the effects of how Britons live on how they feel.
Ian Mulheirn, director of consulting at Oxford Economics, said: "Wellbeing is rising up the agenda at a time of rapid change in how we live our lives, and we've created a critical new tool that can help us to unpick what's driving our sense of living well, drawing on a unique, rolling survey of unprecedented breadth and granularity.
"The analysis within the Sainsbury's Living Well Index reveals that, in a world that's never been more connected, the richness of our relationships and support networks remains among the biggest determinants of how well we live, and represents an area of our lives in which we can act."
Sainsbury's chief executive Mike Coupe said: "We've launched the Sainsbury's Living Well Index to help us better understand what 'living well' truly means to people across the UK today.
"The index will help to inform how we run our business and will also help us uncover and engage more boldly on the issues that concern people most in their everyday lives."