How to compare team capacity before committing to a software deadline

What most people expect Change the team → change the timeline. More devs → faster delivery. What actually happens In many cases, the timeline barely changes. But: Same duration. Very different execution risk. Why? Because: The total work stays the same The steps are still sequential (design → build → test → deploy) Someone still has to do each step So instead of reducing time, you just redistribute it. What really changes Different team setups change how your project behaves: idle time between steps how busy each person is how much coordination is needed where bottlenecks appear Not necessarily the final date. What this looks like in practice You can run 3 different team setups and still get ~4 weeks. But: one has overloaded devs one has idle time one has smoother flow This is why many projects don’t fail because of bad estimates. They fail because the execution model was never stress-tested. If your planning process only outputs a date, you’re missing the part that actually determines