India’s population is expected to peak around 2064 at roughly 1.7 billion people, according to the United Nations’ medium-variant projection. That’s about 240 million more than today’s 1.46 billion. But the country’s fertility rate has already dropped below the replacement level of 2.1 children per woman, hitting 2.0 in the most recent national health survey (2019-21), which means the momentum driving growth is largely demographic inertia rather than high birth rates.
Why the Population Keeps Growing After Fertility Falls
A fertility rate below replacement doesn’t mean the population shrinks immediately. India has an enormous base of young people, with a median age of just 28. As these hundreds of millions of young adults move through their childbearing years, total births remain high even though each family is having fewer children. This lag between falling fertility and an actual population peak is called demographic momentum, and in a country of India’s size, it plays out over decades.
Only Five States Still Have High Fertility
The national average masks a dramatic split. Out of all Indian states and union territories, only five had fertility rates above replacement level in the 2019-21 survey: Bihar (3.0), Meghalaya (2.9), Uttar Pradesh (2.4), Jharkhand (2.3), and Manipur (2.2). Every other state and territory was already at or below 2.1. Sikkim had the lowest rate in the country at 1.1, while Goa, Ladakh, and the Andaman and Nicobar Islands were all at 1.3.
The states still above replacement are also among the most populous. Bihar and Uttar Pradesh alone account for roughly a quarter of India’s population, so their higher fertility rates carry outsized weight in the national trajectory. These two states, along with Rajasthan and Madhya Pradesh, are projected to contribute the largest share of India’s remaining population growth, with annual growth rates between 0.8 and 1.1 percent over the coming decades.
The North-South Divide
India is essentially running two demographic timelines at once. Southern states like Kerala, Tamil Nadu, and Andhra Pradesh have fertility rates well below replacement and growth rates far under the national average. The entire southern region is expected to begin losing population after 2041, essentially holding steady at its 2021 population level through 2051 and then declining. Its share of India’s total population is projected to fall from 20 percent to 17 percent.
Meanwhile, the northern and central regions, anchored by the Hindi-speaking heartland, will see their combined population share rise from 48.6 percent to a projected 52.7 percent. This geographic shift has significant political and economic implications, as a shrinking south subsidizes a still-growing north through tax revenue, while representation in parliament is tied to population counts.
What’s Driving Fertility Down
The same forces reshaping demographics across the developing world are at work in India: urbanization, poverty reduction, and rising education levels among women. Fertility declines have been sharpest in cities and towns, where women tend to marry later, stay in school longer, and participate more in the workforce. Urban fertility had already fallen to 1.7 children per woman by 2017, years before the national average crossed below replacement.
Southern states, which include tech hubs like Bangalore, reached low fertility earlier in part because of higher education levels and later marriage ages. As these patterns spread to northern states through continued urbanization and expanding access to education, the remaining pockets of above-replacement fertility are expected to close.
The Demographic Sweet Spot: 2025 to 2035
India is entering what economists call its demographic window, the period when the share of working-age people (15 to 64) relative to children and the elderly is at its highest. This sweet spot is projected to run from 2025 to 2035, representing the country’s best chance to convert a large, young workforce into economic growth before aging pressures set in.
The window is finite. By 2046, India’s elderly population is expected to outnumber its children (those under 15) for the first time. By 2050, people aged 60 and over will make up roughly 20 percent of the total population, double the current share. The elderly population’s decadal growth rate is already around 41 percent, far outpacing overall population growth.
What Happens After the Peak
Once the population peaks around 2064, India will begin a gradual decline. Under the UN’s medium projection, the population is expected to fall to around 1.5 billion by 2100, shedding roughly 200 million people in the final decades of the century. If fertility drops faster than expected, as some alternative models suggest, the peak could arrive sooner and the decline could be steeper.
The post-peak era will bring challenges that mirror what Japan, South Korea, and parts of Europe are already facing: a shrinking workforce supporting a growing number of retirees, rising healthcare costs, and potential labor shortages. India’s advantage is time. The country still has decades to build the economic infrastructure, pension systems, and healthcare capacity needed to manage an aging society. Whether it uses that time effectively will shape how the transition feels for the generation that lives through it.