London vs. Tehran: Which City Is Bigger?

The answer depends on how you measure "bigger" — land area or population.

Land Area

➡️ London is 2.15× larger by land area.

Population (2023–2024 Estimates)

➡️ Essentially tied for city-proper population. Both ~9M.

Metropolitan Areas

➡️ Tehran metro slightly larger by population; London metro larger by area.

Why the Confusion?

• Different boundary definitions: Tehran's municipal limits are tight; London's are expansive (Green Belt included)
• Density: Tehran ~12,000/km²; London ~5,600/km² — Tehran feels more intensely urban
• Growth: Tehran's metro expands rapidly; London's constrained by Green Belt

Other Comparisons

• Economic output: London GDP ~£500B; Tehran ~$150B (PPP higher)
• Global city rank: London = Alpha++ (top tier); Tehran = Beta+ (regional hub)
• Transit: London Underground (402 km); Tehran Metro (250+ km, expanding fast)
• Green space: London 47% green/blue; Tehran <10% (air quality challenges)

Bottom line: London is larger by administrative area; populations are nearly equal; Tehran's metro may edge out London's. Two megacities, different continents, each the heartbeat of its nation.