How many people live on Earth?

How to get close to this number

This is the anchor number the rest of the site hangs off, and it is worth committing to memory rather than deriving. Almost every global question here — bananas, cigarettes, cattle, cars, emails — is answered by taking this figure and applying a per-person rate, so knowing it to one significant figure unlocks dozens of others.

The rate of change is the part people get wrong in both directions. The world still adds around seventy million people a year, which sounds enormous, but the growth rate has more than halved since the 1960s and continues to fall. Absolute growth and rate of growth move in opposite directions for a while, and conflating them produces confident wrong predictions.

The concentration in the explanation is what the future depends on: almost all remaining growth comes from two regions. Global population projections are not statements about humanity in general but about a small number of countries, which is why the Africa and Nigeria questions on this site are really questions about the world total.