For public presentations, popular slide presentation programs offer a presenter mode, that shows on one screen the current, next, and previous slides, the time elapsed on this slide and the total time elapsed, and also any notes attached to the slides. This is all shown while on the other screen it just shows the presentation contents.
This can also be achieved in beamer, with a third-party program Pympress. Pympress is a free PDF presentation tool designed for dual-screen setups such as presentations and public talks. It comes with very useful features, such as:
- Two-screen display: you can see on your laptop or tablet display the current slide, the next slide, the talk time and the wall-clock time, and annotations.
- Media support: supports playing video, audio, and GIF files embedded in (or linked from) the PDF file.
- Highlight mode: allows one to draw freehand on the slide currently on screen.
- Go to slide: You can jump to a selected slide without having to go through the whole presentation.
- Software pointer: you can emulate a laser pointer with your mouse.
- Talk time breakdown: the Timing Breakdown menu item displays a breakdown of how much time was spent on each slide, with a hierarchical breakdown per chapters, sections, …if available in the PDF.
- Estimated talk time: The Time Estimation box lets you set a planned talk duration. The color will allow you to see at a glance how much time you have left.
And many more that you can find in their documentation.