How much space would it take for everyone on Earth to stand in one place?

At a packed-crowd density of about four people per square metre, roughly 8.2 billion people occupy around 2.05 billion square metres, which is 2,050 square kilometres. Luxembourg is 2,586 square kilometres, so everyone alive would fit inside it with room left over; the city of Los Angeles covers about 1,300 square kilometres, so it would take a little under two of them. At a more comfortable one person per square metre the figure rises to about 8,200 square kilometres, still smaller than Puerto Rico. The number is worth knowing because it corrects a persistent intuition that the planet is physically full: Earth's land area is about 149 million square kilometres, so the standing-room figure is roughly a seventieth of one per cent of it. What limits population is the land needed to feed, water and supply people, not the land they stand on.

How confident this is

This is a reasoned extrapolation rather than an observation. The mechanism is understood, but the scale of the consequences depends on assumptions that could reasonably be argued differently.

Everyday systems

• What would happen if everyone on Earth jumped at the same time? Essentially nothing. All of humanity together is about one ten-trillionth of Earth's mass.
• What would happen if the internet went down? Payments fail first, then logistics — most physical supply chains now depend on network connectivity rather than the other way round.
• What would happen if all the power went out worldwide? Water supply is the first life-critical failure — most tap water is pumped, and pumping stops when the grid does.
• What would happen if GPS stopped working? Timing, not navigation, is the real dependency — mobile networks, power grids and financial systems all use GPS clocks.
• What would happen if money stopped existing? Trade would collapse to what barter can support, and something money-like would be reinvented within weeks.
• What would happen if all the satellites stopped working? Weather forecasting would lose most of its accuracy beyond a day or two, along with navigation, timing and most long-range communications.
• What would happen if all refrigeration stopped? Food waste would rise enormously and the vaccine cold chain would fail — refrigeration is a public health system, not a convenience.
• What would happen if the water supply stopped? Three days for drinking, but sanitation fails first — waterborne disease is what historically kills people in a water outage.
• What would happen if all digital data was lost? Ownership would be the deepest problem — land registries, bank balances and medical records exist almost entirely as data.