A bar filling from one end to show how much of a task remains.
A horizontal bar filling from left to right shows how far through a task the system is. Where the remaining work genuinely cannot be estimated, an indeterminate variant animates instead of filling.
Shows the proportion of an operation completed, by the fraction of the bar that is filled.
Contexts: Software
An indeterminate variant animates without filling, which is an admission that the remaining work cannot be estimated rather than a claim about it.
Contexts: Software
A long horizontal rectangle outline whose left portion is filled solid, the boundary between filled and empty marking how far the task has run.
Both are used in software contexts.