Island and municipality
The municipality reports 252 km² in total, of which the main island accounts for 227 km².
Atlas uses the recognisable island outline for area while explaining that population has the wider municipal scope.
Place profile
How big is Koh Samui?
Also known as: Ko Samui
Koh Samui covers 227 km² (87.6 sq mi) of land and had a population of 69,689 in 2024, about 307 people per km² (795 per sq mi). In more familiar terms, it is about 1.43 times the size of Washington, D.C..
Compare this place- Area
- 227 km² · 87.6 sq mi
Source accessed:
- Population
- 69,689
Reference date:
- Population density
- 307 people/km² · 795 per sq mi
Calculated from the population and area above; their reference dates may differ.
- On a familiar scale
- ≈ 1.43 × Washington, D.C. (reference rung)
The closest rung on the US reference ladder (Census Bureau land area); see the sources below.
- Land per resident
- 3,257 m² of land per resident
The inverse of population density, from the same area and population figures.
Change the yardstick
Koh Samui is “how many times” what?
The multiples on this site default to Taiwan. Pick a place you know and the area, population and density are recalculated against it; your choice is remembered in this browser and carries to other pages.
- Area
- Population
- Population density
Scope and definitions
Area is for Koh Samui main island. Population is the 2024 Ko Samui City Municipality total, whose 252 km² administration includes the 227 km² main island and 18 surrounding islands; density is therefore approximate for the main island.
Average administrative density does not describe population distribution in every neighborhood. Compare population definitions and reference dates alongside the numbers.
Place guide
How should this Koh Samui profile be read?
Koh Samui is represented by the 227 km² physical main island. Its best current official population is municipal and covers eighteen additional islands, making density approximate.
Good uses and limits
Area comparisons with Penghu, Hong Kong and Green Island remain useful for visual scale.
Density should remain labelled approximate and must not be used to predict tourist crowding.
Questions people ask
About Koh Samui’s area and population
How big is Koh Samui?
Koh Samui covers 227 km², or 87.6 sq mi (source accessed 2026-09-05). In US terms: ≈ 1.43 × Washington, D.C..
What is the population of Koh Samui?
69,689 as of 2024-12-31. The scope of that count is set out under “Scope and definitions” on this page.
What is the population density of Koh Samui?
About 307 people per km² (795 per sq mi), derived from the area and population above, whose reference dates may differ. An administrative average does not describe how crowded any particular neighbourhood is.
What do these Koh Samui figures include?
Area is for Koh Samui main island. Population is the 2024 Ko Samui City Municipality total, whose 252 km² administration includes the 227 km² main island and 18 surrounding islands; density is therefore approximate for the main island.
What else is Koh Samui called?
Also written or known as Ko Samui. Every one of those names refers to the place measured on this page.
Data sources
- Ko Samui City Municipality: General information: municipal and main-island area
- National Statistical Office, Thailand: Surat Thani Provincial Statistical Report 2025, Table 1.2
- U.S. Census Bureau: 2025 Gazetteer Files: land area of states and counties · US reference ladder
Outline source: © OpenStreetMap contributors · ODbL · source feature
Read the methodology and data notesRelated comparisons
- Koh Samui compared with Penghu: area, population and density
- Koh Samui compared with Hong Kong: area, population and density
- Green Island compared with Koh Samui: area, population and density
- Phuket compared with Koh Samui: area, population and density
- Koh Pha-ngan compared with Koh Samui: area, population and density
- Phu Quoc Island compared with Koh Samui: area, population and density
- Koh Samui compared with Singapore: area, population and density