I use this to give a workout a place in your calendar. The estimate adds up the time you enter; it does not tell you how long a good workout should take or how your session compares with anyone else's.
What the estimate includes
I assume every exercise has the same sets, reps, seconds per rep and rest. There is rest between working sets within an exercise, with no extra rest after its last set. Setup is counted for every exercise, including the first. Warm-up is a separate total, so include any warm-up sets there. Supersets and overlapping work or rest are outside this calculation.
A worked example
With the prefilled inputs, I have 5 exercises, 3 working sets each, 8 reps per set and 4 seconds per rep. That is 480 seconds, or 8 minutes of work. Two 90-second rest periods per exercise add 15 minutes, and 120 seconds of setup per exercise adds 10 minutes. The 8-minutewarm-up brings the unpadded total to 41.0 minutes.
For the realistic estimate, I multiply the 33 minutes of work, rest and setup by 1.15, then add the 8-minute warm-up. That gives 45.95 minutes, displayed as 46 minutes. The flat 15 percent allowance is my planning choice for delays, not a measured figure or a guarantee. Your session may take more or less time.
When I would recalculate
I would compare the estimate with the clock after trying the session. If setup or rest took longer, update those inputs. Once the estimate fits your routine, there is no reason to recheck it on a calendar.Recalculate when you change the workout or your usual timings. A smaller share of working minutes is not a grade on the session.