TurtleBar

TurtleBar replaces a battery percentage with time left. It reads the watts your Mac is drawing right now and divides the remaining charge by that, like a trip computer, then shows a countdown in the menu bar. The estimate catches up within about a minute when your workload changes, shows an adjusting state while it does, and learns what your Mac draws at each hour so projections such as the time it will empty reflect your day.

A Make it last until feature lets you set a time, such as the end of a flight or a meeting, and tells you whether you will make it and by how much. If you will fall short, you get one notification and the app can switch on Low Power Mode, including automatically before you run out, and shows how much time it would add. The site also describes power rules per app.

It supports MacBook Air and Pro on macOS 13 or later, on Apple Silicon and Intel, and is signed and notarized by Apple. It costs $4.99 once with no subscription and a 14-day refund. Its FAQ and guides explain how the estimate works and why Apple removed time remaining from the menu bar in 2016.