Simulation time during a Variable timestep

Dear all,
I hope you are doing great.
I am just wondering how I can adjust the simulation time if I am using a variable time step.
For example, If I am using a real unit, to simulate 1 PS I can set the timestep to be 1.0 fs and the run to be 1000. But when I am using a variable timestep how can I determinate the run (…) value?
Thank you!

You cannot. You will know, however, from testing what the typically applied timestep will be. Assume the smallest of those values and your simulation will be at least minimum time you require. Running for longer usually is not a problem. Better statistics have never hurt anybody.

If you absolutely want a simulation to stop after a given elapsed simulation time, you can use fix halt in addition to overestimating the number of required steps.

Dear Axel,
Many thanks!