Imagine cramming every single human being on Earth – over 8.2 billion of us – onto a colossal scale. What would the reading be? It’s a mind-boggling question that blends demography, biology, and a dash of environmental science.
As of August 2025, the total weight, or biomass, of all humanity is estimated at around 390 million metric tons. That’s 390 billion kilograms of flesh, bones and everything in between. This figure comes from detailed scientific analyses that account for population size, average body weights across regions, and even the contributions from children and adults alike. To put it in perspective, that’s roughly the same as 2.6 billion average-sized elephants or about 65,000 Great Pyramids of Giza (each weighing around 6 million tons).
The world’s population stands at approximately 8.24 billion people as of mid-August 2025, according to real-time estimates from reliable sources like Worldometer. This number has grown steadily from about 7.8 billion in 2020, driven by birth rates outpacing deaths in many regions. But weight isn’t uniform—far from it.
The global average body weight, including children, hovers around 47-50 kilograms per person. Why so “low” compared to adult averages? Children under 15 make up about 25% of the global population (roughly 2 billion people), and their average weight is significantly lighter, often around 20-25 kg depending on age and nutrition.
For adults alone, the story is different. A landmark 2012 study using 2005 data estimated the global adult biomass at 287 million metric tons for about 4.6 billion adults, yielding an average of 62 kg. This average varies wildly by region: Asians averaged 57.7 kg, while North Americans tipped the scales at 80.7 kg. Fast-forward to today, and rising obesity rates have pushed averages higher in many places. The World Health Organization reports that in 2022, 43% of adults were overweight, with 16% obese, adding extra biomass equivalent to millions of additional people.
Interestingly, if the entire world adopted the body mass index (BMI) distribution of the United States (average BMI 28.7 in 2005), global human biomass would balloon by an additional 58 million metric tons—equivalent to the weight of about 935 million average adults. Conversely, if everyone matched Japan’s slimmer profile (average BMI 22.9), we’d shed 14.6 million tons, a 5% drop.
Humans might dominate the planet intellectually, but our collective heft tells an even more dramatic story. At 390 million metric tons, humanity outweighs all wild mammals on Earth by a factor of about six. Wild land mammals—like elephants, lions, and deer – total just 22 million metric tons, while wild marine mammals (whales, seals, etc.) add another 44 million tons, for a grand total of 66 million metric tons. Baleen whales alone contribute 8 million tons, and sperm whales another 7 million – impressive, but still dwarfed by us.
Our domesticated animals steal the show, though. Cattle, bred for meat and dairy, weigh in at 420 million metric tons, slightly more than all humans combined. Dogs, our loyal companions, match the biomass of all wild land mammals at 21 million tons. In total, humans and our livestock account for over 95% of all mammal biomass on the planet, leaving wild mammals with a mere 4-6% slice. This shift is a stark indicator of human impact: before agriculture and industrialization, wild mammals vastly outweighed us.
Zooming out further, humanity is a tiny fraction of Earth’s total living biomass. All life on the planet weighs about 2.2 trillion metric tons (wet weight), with plants dominating at around 80%. Bacteria alone could outweigh us by orders of magnitude if measured in carbon content. In carbon terms, humans represent just 0.06 gigatons of carbon (Gt C), a sliver of the global 550 Gt C.
Humanity’s weight hasn’t always been this hefty. In 1900, with a population of about 1.6 billion and lower average weights due to poorer nutrition, our total biomass was likely under 100 million tons. By 2005, it had climbed to around 320-350 million tons (including children estimates). The surge since then—about 20-30% in two decades—stems from population growth (now at 1% annually) and increasing body sizes from better food access and sedentary lifestyles.
Looking ahead, projections suggest the world population could peak at 10.4 billion by 2100, potentially pushing our collective weight past 500 million tons if average weights continue rising. However, factors like aging populations (older adults weigh less on average) and global efforts to combat obesity could temper this. One sobering fact: human-made materials – concrete, plastics, metals – now total about 1.1 trillion tons, surpassing all living biomass on Earth. This “anthropogenic mass” doubles every 20 years, highlighting our outsized footprint.
Our 390 million tons may seem abstract, but it translates to real demands: more food, water, and energy to sustain us. The extra biomass from obesity alone requires the equivalent of feeding hundreds of millions more people. Environmentally, our weight symbolizes dominance— we’ve reshaped ecosystems, reducing wild animal biomass to fractions of what it once was. Yet, it also underscores vulnerability: climate change, resource scarcity, and pandemics could shift these scales dramatically.
In the grand scheme, humanity’s literal weight is a testament to our success as a species. But as we pile on the pounds collectively, it’s a reminder to tread lightly on a planet that can’t bear unlimited burdens. Next time you step on a scale, remember: you’re part of something much bigger – and heavier – than you think.
© Preems