Total population and population densityboth answer questions about people and countries, but they're not measuring the same thing — and mixing them up leads to some very wrong intuitions about the world.
The difference, precisely
Total population is a headcount — every resident, added up. Population density is that headcount divided by land area — people per square kilometer. A country can rank near the top of one list and near the bottom of the other, because they depend on completely different things: population depends only on how many people live there; density also depends on how much room they have.
Large population, low density
Russia has a population of 143.5M — the 9th largest in this dataset — but ranks only 183rd of 196 by density. A large population spread across a vast territory produces a low density average, even though the raw population number is enormous.
Large population, high density
Bangladesh shows the opposite combination: 173.6M people (the 8th largest population here) packed into a comparatively small land area, giving it a density of 1,335 / km² — 6th highest in this dataset. Large population and high density aren't mutually exclusive; they just require a large number of people and a small territory at the same time.
Small population, extreme density
At the other end, Nauru has one of the highest population densities in this dataset despite ranking only 195th of 196 by total population. Its raw population is unremarkable — the density comes entirely from having very little land area to spread across. This pattern is common among small, urbanized city-states.
Why the distinction matters
Density, not raw population, is what actually drives most of what people mean when they call a place "crowded" — housing pressure, traffic, how far things are from each other. Total population, on the other hand, is what mostly drives a country's aggregate economic size and political weight. Neither number tells you the other; you need both to get a real picture of a country's demographic profile.
All figures computed live from this site's population and land-area datasets (World Bank SP.POP.TOTL and AG.LND.TOTL.K2) — see the population and density pages for full, sortable rankings and methodology.