A hiking time calculator has to price the climb. This one uses your flat pace for the miles and your climbing rate for the gain, then checks the grade with Tobler so a steep mile is slower than a gentle one. Breaks are added after the moving time. An out-and-back splits the distance in half and puts the gain on the way out and the loss on the way back.
You can type the miles, or upload a GPX file. The track is split into about a mile at a time, with the gain and loss of each piece. The file itself is not stored.
The total time is free. $5 unlocks the segment table, the turnaround clock, and a CSV. Training for the day lives in Big-Hike Prep.
Turnaround is a pace sketch from Naismith and Tobler, not a guide and not a weather report. Leave earlier for storms, a slow group, or a route you do not know. A headlamp does not make a late return safe.