How the calculation works
Quicklio multiplies expected trick-or-treaters by your pieces-per-child plan, adds your buffer, then rounds up to whole bags.
How much buffer?
The buffer is your planning choice. Use more when turnout is unpredictable and less when you have reliable history.
Why save last year's count?
Your own address history is usually more useful than a generic neighborhood label. The saved number stays in this browser.