One of the most powerful arguments for gender equality is not moral but arithmetic: when half the population is held back from full economic participation, the whole economy grows more slowly than it could. Economists have spent the past decade putting numbers on that lost potential, and the numbers are staggering — measured not in millions or billions but in tens of trillions of dollars. The exact figure depends heavily on how you frame the question, so it is worth walking through the major estimates carefully rather than repeating a single headline.
The scale of what is left on the table
The most direct answer to “how much is the gender gap costing us?” comes from the World Bank’s 2018 study Unrealized Potential: The High Cost of Gender Inequality in Earnings, which covered 141 countries. Its central finding is arresting: gender gaps in lifetime earnings cost the world an estimated $160 trillion in lost human capital wealth — roughly $23,600 for every person on the planet. Put another way, the study concluded that global human capital wealth is about 20% lower than it could be purely because women earn less than men over their lifetimes. Women hold just 38% of the world’s human capital wealth, against 62% for men.
That “20% lower” figure is almost certainly the origin of the popular claim that closing the gender gap could raise the global economy by a fifth. It is a real and well-sourced number — but it refers specifically to human capital wealth, the discounted value of people’s future earnings, rather than to annual GDP. The distinction matters for accuracy, though both point to the same underlying truth: the world is leaving an enormous amount of prosperity uncollected.
The GDP estimates: from $12 trillion to $28 trillion
If we want figures expressed as GDP rather than wealth, the landmark reference is the McKinsey Global Institute’s 2015 report The Power of Parity. It modelled two scenarios. In a “full potential” scenario — where women participate in the economy identically to men — global annual GDP could be $28 trillion, or 26%, higher by 2025. Because full identical participation is unrealistic in any short timeframe, McKinsey also modelled a “best-in-region” scenario, in which every country simply matches the pace of improvement of its fastest-improving neighbour. Even that more modest path would add $12 trillion to global GDP — an amount roughly equal to the combined economies of Japan, Germany and the United Kingdom at the time.
The International Monetary Fund has approached the same question from the angle of labour-force participation. Its 2023 analysis found that closing gender gaps in participation would raise GDP by an average of about 8% in emerging-market economies, 7% in low-income developing countries, and 5% in advanced economies. Crucially, the IMF argues these are conservative figures, because they capture only the effect of more workers. When you add the “diversity dividend” — the gains that come from men and women bringing complementary skills and perspectives rather than being interchangeable — the potential increase can be substantially larger, in some economies well into double digits.
Why the estimates differ so much
A reader encountering figures ranging from 5% to 26% might reasonably ask which is correct. The answer is that they are measuring different things. The lower IMF numbers isolate a single channel: the effect of raising women’s labour-force participation to match men’s. The higher McKinsey “full potential” figure bundles in several channels at once — more women working, women working more hours, and women moving out of low-productivity sectors into higher-productivity ones. Neither is wrong; they answer different questions. The honest way to present the evidence is to say that credible estimates of the prize range from several percent of GDP (participation alone) up to roughly a quarter of GDP (full parity across every dimension), with tens of trillions of dollars at stake under any serious scenario.
How it works in practice
The abstraction becomes concrete when you trace the individual mechanisms.
The first is simply getting more women into paid work. In many countries, female labour-force participation still trails male participation by 20 or 30 percentage points. Every woman who wants a job and cannot get one — because of childcare costs, legal restrictions, discrimination or lack of transport — is productive capacity sitting idle. Countries that have narrowed this gap, from Spain to parts of Latin America, have seen measurable growth dividends.
The second is hours and quality of work. Women are disproportionately concentrated in part-time and informal employment, often not by choice but because of caregiving responsibilities. Policies that make full-time work compatible with family life — affordable childcare, paid parental leave shared between parents, flexible scheduling — allow women to move into more productive, better-paid roles.
The third is sectoral allocation. When talented women are steered away from high-productivity fields such as engineering, finance and technology, the economy loses the output they would have produced there. Improving access to these sectors raises average productivity, not just employment.
The fourth is the intergenerational multiplier. Women who earn independent incomes tend to invest more heavily in their children’s health and education, which raises the productivity of the next generation. This is why development economists treat women’s economic empowerment as one of the highest-return investments available to a poor country.
From theory to policy
The practical levers are well understood and, in many cases, already tested. Investing in public childcare has repeatedly been shown to raise maternal employment. Reforming laws that restrict what jobs women can hold or whether they can own property removes direct legal brakes on participation — the World Bank’s Women, Business and the Law project documents how many economies still maintain such restrictions. Closing the gender gap in access to finance unlocks women-owned businesses. And designing tax and benefit systems so that second earners (usually women) are not penalised for working can shift household decisions at the margin.
Case studies: where the theory has been tested
The mechanisms are not merely theoretical; several economies have run versions of the experiment and produced measurable results.
The most-cited success story is the Nordic model, and Iceland is its sharpest illustration. Iceland has topped the World Economic Forum’s gender-gap rankings for well over a decade, and it did so partly by building one of the world’s most comprehensive systems of subsidised childcare and shared parental leave — including leave earmarked specifically for fathers. The result is one of the highest female labour-force participation rates in the world, and a female employment rate close to the male one. Norway, Sweden and Denmark followed similar paths, and all combine high female participation with strong economic performance — direct evidence that generous care infrastructure and high women’s employment are complements, not trade-offs.
At the opposite end, the cost of exclusion is visible in economies where legal and social barriers keep women out of the workforce. The World Bank’s Women, Business and the Law project documents that in a significant number of economies, women still face legal restrictions on the jobs they can hold, their ability to open a bank account, own or inherit property, or travel without permission. Each such restriction is a direct brake on participation, and the economies that maintain the most restrictions tend to have the lowest female employment and, correspondingly, the largest untapped growth potential. Reforms that remove these legal barriers have been followed by measurable increases in women’s economic activity.
A middle case is Japan, whose “womenomics” agenda — an explicit government strategy launched in the 2010s to raise female participation as a response to a shrinking, ageing workforce — succeeded in pushing women’s labour-force participation to record highs, in some measures surpassing that of the United States. Yet Japan’s experience also illustrates the limits of participation alone: many of the new jobs were part-time and lower-paid, and women remained scarce in management, so the pay and leadership gaps persisted even as employment rose. The lesson is that getting women into work is necessary but not sufficient; the quality and seniority of that work determines how much of the potential GDP is actually captured.
Demographics make this urgent, not optional
There is a demographic dimension that turns the gender dividend from a nice-to-have into a necessity. Much of the developed world, and increasingly parts of the developing world, faces ageing populations and shrinking workforces. In that context, the pool of underemployed women represents the single largest available source of additional labour. Countries that fail to draw women fully into the economy will face labour shortages and slower growth that no amount of other policy can easily offset. Raising female participation is, for many ageing societies, less a matter of fairness than of economic survival — a way to sustain output and the tax base that funds pensions and healthcare as the ratio of workers to retirees deteriorates.
The intergenerational multiplier in detail
The most powerful long-run mechanism deserves emphasis. A large body of development economics finds that income in women’s hands is spent differently from income in men’s hands — with a greater share going to children’s nutrition, health and education. This means that raising women’s earnings does not merely add to this generation’s output; it raises the human capital, and therefore the productivity, of the next. The effect compounds across generations. It is one reason institutions from the World Bank to UNICEF treat investment in women’s economic empowerment as among the highest-return interventions available to a developing economy — the returns arrive not once but repeatedly, in the improved capabilities of the children those earnings help raise.
The distributional question
An honest account must address a subtlety that headline GDP figures obscure: growth and equality are not automatically the same thing, and how the gender dividend is distributed matters as much as its size. Bringing millions of women into paid work raises aggregate output, but if those women enter low-paid, insecure, informal jobs, the human gains can lag the economic ones. The point of closing the gender gap is not merely to add bodies to the labour force but to give women genuine economic agency — decent pay, security, advancement and control over their own earnings. This is why the more sophisticated models distinguish between simply raising participation and raising participation into good, productive, fairly-paid work. A strategy that treats women as a cheap labour reserve to be switched on during shortages and off during downturns captures only a fraction of the available prize and does little for equality. The full dividend — economic and human — is realised only when women’s increased participation comes with the pay, conditions and opportunities that make it real empowerment rather than mere employment.
Why this is not a zero-sum transfer
A common intuition, and a source of resistance, is that gains for women must come at men’s expense — that a job or promotion given to a woman is one taken from a man. The macroeconomic evidence contradicts this. Closing the gender gap does not redistribute a fixed pie; it grows the pie. When women enter productive work, they create demand as well as supply — spending their earnings, paying taxes, starting businesses that employ others, and raising more productive children. Economies with high female participation are not economies where men have been displaced; they are larger, more dynamic economies overall. The IMF’s “diversity dividend” captures part of why: men and women often bring complementary skills, so their combined contribution exceeds the sum of interchangeable workers. The framing of gender equality as a transfer from men to women is not only morally cramped but factually wrong; the more accurate framing is that everyone, men included, is currently poorer than they would be in a world that used all its talent.
None of this is charity. It is, on the evidence, one of the largest available sources of growth in the global economy — a prize measured in the trillions, hiding in plain sight.
Sources: World Bank, Unrealized Potential: The High Cost of Gender Inequality in Earnings (2018) and The Cost of Gender Inequality update (2020); McKinsey Global Institute, The Power of Parity (2015); International Monetary Fund, Countries That Close Gender Gaps See Substantial Growth Returns (2023); World Bank, Women, Business and the Law.