How Long Is the World's Coastline? Understanding the Measurements and Variations

Coastline length is not a fixed number. It depends on the scale of measurement (the "coastline paradox": finer rulers yield longer lengths), methodology (satellite vs. chart vs. GPS), and dynamic processes (erosion, accretion, sea-level rise).

Major Estimates

Longest National Coastlines

1. Canada: ~151,000 miles (243,000 km) — Guinness World Record
2. Norway: ~58,000 miles (fjords drastically increase length)
3. Indonesia: ~34,000 miles (archipelago)
4. Greenland: ~27,000 miles
5. Russia: ~23,000 miles

Why the Discrepancy?

• Fractal nature of coastlines: measuring at 1 km vs. 1 m intervals yields vastly different totals.
• Inclusion/exclusion of islands, estuaries, tidal flats.
• Data vintage: older surveys vs. modern LiDAR/satellite.

Practical Takeaway

Always cite the source, scale, and year when quoting coastline figures. For policy or science, use consistent, documented methodologies.