How Big Must a Water Body Be to Be a Lake? ≥1 Hectare (Ramsar)

No universal size threshold exists, but the Ramsar Convention on Wetlands provides a widely used benchmark:

Minimum lake size: 1 hectare (ha) = 2.47 acres = 10,000 m².

Context

• Pond vs. lake: Often distinguished by depth (lakes stratify thermally; ponds don't) and wave action, not just area.
• Regional definitions vary: Some US states use 5–10 acres; Minnesota uses 10 acres.
• Scientific usage: Limnologists focus on processes (stratification, light penetration, residence time) over arbitrary size.

For international wetland inventory and conservation, 1 ha is the standard minimum.