Can money buy happiness? What the research actually says

"Money can't buy happiness," or so the saying goes. Researchers who have surveyed hundreds of thousands of people reach a more nuanced conclusion.[1]Kahneman, D. and Deaton, A. (2010). High income improves evaluation of life but not emotional well-being. PNAS. Money makes people a little happier, and less so the more of it they have. That nuance explains why the richest people are not much happier than everyone else. It also explains why a single euro matters so much to someone who has very little.

Marie d'Ovidio

Mieux Donner · Reading time: 9 min

Feeling happy or rating your life: what are we measuring?

Ask someone "are you happy?" and you could be asking two very different questions.

These two measures respond to money in different ways. Much of the confusion around whether money buys happiness comes from mixing them up.

The "happiness salary": the story of a stubborn number

2010: Kahneman and Deaton find a ceiling, but only for emotions

In 2010, the psychologist Daniel Kahneman and the economist Angus Deaton, both Nobel laureates in economics, analysed more than 450,000 responses to a daily Gallup survey in the United States.[1]Kahneman, D. and Deaton, A. (2010). High income improves evaluation of life but not emotional well-being. PNAS.

Their finding fits in two sentences. Life evaluation rises steadily with income, with no ceiling. Emotional wellbeing rises too, then stops improving at around €66,000 a year ($75,000).[2]Federal Reserve, via FRED (2026). U.S. Dollars to Euro Spot Exchange Rate, 2025 annual average.

The number then took on a life of its own, as a "happiness salary" beyond which earning more would make no difference.

2021: Killingsworth finds no ceiling

In 2021, the researcher Matthew Killingsworth returned to the question with a different method. An app sent notifications at random moments of the day and asked participants how they felt. He collected more than 1.7 million responses from 33,391 employed adults in the United States.[3]Killingsworth, M. (2021). Experienced well-being rises with income, even above $75,000 per year. PNAS.

His result contradicted the 2010 study: experienced wellbeing kept rising above €66,000.

2023: the two sides reanalyse the data together

Kahneman and Killingsworth then decided to reanalyse the data together, with the psychologist Barbara Mellers. Researchers call this an adversarial collaboration: two teams who disagree design, together, the analysis that will settle the question.

Their conclusion, published in 2023, reconciles the two studies:[4]Killingsworth, M., Kahneman, D. and Mellers, B. (2023). Income and emotional well-being: A conflict resolved. PNAS.

• among the least happy people (around 20% of the sample), happiness rises with income up to about €88,000, then levels off;
• for everyone else, it keeps rising. Among the happiest, it even rises faster above that threshold.

According to the authors, the problems of the least happy people stop responding to money beyond a certain income. The 2010 threshold therefore marks the limit of what money can do against some kinds of unhappiness.

More money, a little more happiness: the logarithm rule

What the numbers show

Start with France. According to Insee, French people give the life they lead an average score of 7.2 out of 10. The poorest 10% give theirs 6.5, and the richest 10% give theirs 8.0.[5]Insee (2025). La satisfaction dans la vie est stable en 2024 (Life satisfaction was stable in 2024). Insee Résultats, SRCV survey.

Money matters. Yet only 1.5 points out of 10 separate the two ends of the income scale, even though their living standards are worlds apart.

Other studies point the same way. The World Happiness Report 2025 links a doubling of income to 0.2 extra points of life satisfaction, other things being equal. Losing your job is linked to a drop of 0.5 points.[6]Plant, M., McGuire, J. et al. (2025). World Happiness Report 2025, chapter 8: Giving to others. In the United States, the 2023 study finds a gap of about 0.5 points out of 10 in experienced wellbeing between households earning €13,000 a year and those earning €220,000.[4]Killingsworth, M., Kahneman, D. and Mellers, B. (2023). Income and emotional well-being: A conflict resolved. PNAS.

Why each euro counts for less when you already have plenty

Researchers describe this relationship as logarithmic. Happiness does not go up a notch with every euro earned, but every time income doubles. Going from €1,000 to €2,000 brings roughly as much as going from €100,000 to €200,000.

Take two people. Jean earns €100,000 a year. Amina lives on €500 a year. If the logarithm rule holds at every income level, doubling either person's income brings a similar gain in happiness. But doubling Jean's income costs €100,000. Doubling Amina's costs €500, 200 times less.

The US studies say nothing about people living on €500 a year. To find out whether the rule holds for them, we need to look at other research.

What about people with very little? Evidence from low-income countries

The GiveDirectly trial in Kenya

The charity GiveDirectly gives cash, with no strings attached, to very poor households in several countries in sub-Saharan Africa. In Kenya, researchers measured the effect of these transfers through a randomised trial. Some households, chosen by lottery, received the money and others did not, so the two groups can be compared.

Depending on the household, the transfer was worth about two and a half months or nearly ten months of its usual spending. Nine months after the first transfers, monthly spending in the households that received money had risen by about 22%. The researchers also measured large increases in psychological wellbeing.[8]Haushofer, J. and Shapiro, J. (2016). The Short-Term Impact of Unconditional Cash Transfers to the Poor: Experimental Evidence from Kenya. QJE.

Unlike the US studies, this is more than a correlation. Because the households were chosen by lottery, the difference can be attributed to the money received.

What the meta-analysis says

One study is not enough. In 2022, researchers at the Happier Lives Institute pooled 37 studies of cash transfers in low- and middle-income countries, covering 112,245 people in total.[9]McGuire, J., Kaiser, C. and Bach-Mortensen, A. (2022). Impact of cash transfers on subjective well-being and mental health in LMICs. Nature Human Behaviour.

Receiving cash improves wellbeing and mental health. The effect is modest for each person, but it lasts: the studies follow participants for two years on average, and the effect fades only slowly.

These results cannot confirm the logarithm rule precisely. They do show that a cash transfer measurably improves the lives of families living in extreme poverty.

Does giving make you happier?

The 2008 experiment

In 2008, Elizabeth Dunn, Lara Aknin and Michael Norton published a simple experiment in the journal Science.[10]Dunn, E., Aknin, L. and Norton, M. (2008). Spending Money on Others Promotes Happiness. Science, 319(5870). They gave a sum of money to 46 participants. Half of them, chosen at random, had to spend it on themselves, and the other half on someone else. Those who spent on others then reported feeling happier.

What the replications show

An experiment with 46 people is fragile. Two teams have repeated it since.

In 2020, Lara Aknin and her colleagues ran a replication with much larger samples. They registered their protocol in advance, so the analysis could not be adjusted after the fact. The effect exists, but it is smaller than expected and depends on how the experiment is run.[11]Aknin, L., Dunn, E. and Proulx, J. (2020). Does spending money on others promote happiness?: A registered replication report. JPSP.

In 2022, another team reproduced the original experiment with 133 participants. Using the happiness measure from 2008, they found no clear difference between the two groups. With a more direct question, they found an effect in the same direction.[12]Kim, G. et al. (2022). Prosocial spending encourages happiness: A replication of the only experiment reported in Dunn, Aknin, and Norton (2008). PLoS ONE.

How much happiness does giving 10% of your income cost?

The link between income and happiness also works in reverse. Giving 10% of your income means living on 90% of it, which is far from halving it. And the gap in wellbeing between a household on €13,000 a year and one on €220,000 is no more than 0.5 points out of 10. A 10% donation should therefore cause only a very small drop, and the pleasure of giving may partly make up for it.

Romain Barbe, Mieux Donner's founder, gives 10% of his income. In his account, he explains that living on 90% has not changed his daily life in any deep way, and that his life now sits closer to his values.

How to spend money to be happier

If money does little for happiness, how you spend it may matter more. In 2011, the psychologists Elizabeth Dunn, Daniel Gilbert and Timothy Wilson drew eight principles from the research:[13]Dunn, E., Gilbert, D. and Wilson, T. (2011). If money doesn't make you happy, then you probably aren't spending it right. Journal of Consumer Psychology.

The second principle is the one that matters here. The question then becomes who to give to, so that the money counts for as much as possible.

What this means for your giving

If each euro counts for less when you have plenty, the same sum weighs far more for someone who has very little. On a global scale, France is a very rich country. A person on €25,760 a year, the median living standard in France,[7]Insee (2025). Niveau de vie et pauvreté en 2023 (Living standards and poverty in 2023). Insee Première no. 2063. is among the richest 6% of the world's population.

This is no reason to feel guilty. It is a reason to think about where the money you choose to give ends up. The World Happiness Report 2025 compared the wellbeing produced by different charities. The most effective produce hundreds of times more per euro than the least effective in the sample.[6]Plant, M., McGuire, J. et al. (2025). World Happiness Report 2025, chapter 8: Giving to others.

The Kenyan trial was about GiveDirectly. From France, a donation to GiveDirectly is not eligible for tax relief. Other charities working with the poorest people are eligible, such as Against Malaria Foundation and Helen Keller International, so you receive tax relief on your donation. These charities do not hand out cash. They fund insecticide-treated mosquito nets and vitamin A supplements for children, two of the best-evaluated interventions to date.

Frequently asked questions

This article draws in part on "Can money buy happiness? A review of the data", published by Giving What We Can (November 2024).