Boiling water usually looks like vigorous, continuous bubbling across the whole pot, with the surface churning and steam rising steadily. Before that, you may see small bubbles on the bottom or sides, which are often just the water warming up rather than a full boil.

What to look for

  • Small bubbles on the bottom or edges usually mean the water is heating up, not fully boiling yet.
  • A simmer has occasional bubbles and only gentle movement at the surface.
  • A rolling boil has large bubbles rising constantly and the water surface looks active and turbulent.

Simple rule

If the whole pot is moving and bubbling hard, it’s boiling. If only a few bubbles are appearing around the edges, it’s probably not there yet.

TL;DR: Boiling water looks like fast, nonstop bubbling with a churning surface and visible steam, not just a few tiny bubbles at the edges.