How should we check the k-means clustering has converged?

Just a general question. How can we check if the K-Means clustering model has converged? The mission explains pretty well that the clusters stop moving after a few iterations. But can we verify that? Sometimes it is not noticeable, if the clusters are moving or not after an iteration.
Is there a way, maybe a metric that can tell us the model has converged? I don’t think visualization is helping us confirm it has converged. Thank you!

I am vaguely familar with k-means. Hope that this article and this other can help you.