Illustrative example. The dates and amounts below are provided for practice.
A couple checks their milestone on April 10, 2027 after starting on January 1. They need to know whether the celebration belongs today or tomorrow.
Enter those dates and choose Inclusive day numbers. Total Elapsed Days is 99 and Inclusive Day Number is 100. The next 100-day milestone is April 10 itself.
Why the next target includes today
The tool includes a milestone reached on the reference date. It does not automatically skip to the next multiple. If you calculate until April 11 instead, the inclusive day number becomes 101 and the next 100-day milestone moves to July 19, 2027, which is Day 200.
With Elapsed days selected, the first 100-day target is April 11. The one-day difference comes from the starting convention rather than a calculation error.
Keep the invitation and count aligned
Write “Day 100 together” when you include the start. If the party is tomorrow for convenience, keep April 10 as the milestone record and give the plan its actual date.
An unqualified “100 days completed” would instead suggest the elapsed target. Agree on the wording before making something permanent, such as a printed album caption.