Calculate your relationship milestones and anniversaries
The traditional relationship timeline — dating, exclusivity, moving in together, engagement, marriage, children — has been significantly disrupted over the past 30 years across most Western countries. Average age at first marriage has risen by 5–7 years since the 1970s. Cohabitation before marriage has moved from socially discouraged to the statistical norm. The sequence of milestones is far more varied, personalised, and non-linear than it was for previous generations.
Milestone awareness in relationships serves several psychological functions. It creates shared narrative — the story of how the relationship developed. It provides anchor points for reflection. It marks commitment escalations — moments when the relationship officially entered a new stage. Research on relationship satisfaction finds that couples who share a clear and positively framed relationship narrative (how we met, the turning points, how we got here) have higher relationship quality and resilience in adversity.
100 days has become a culturally prominent early relationship milestone, particularly in East Asian relationship culture, where "백일" (100 days) celebrations are a recognised tradition in South Korea. The moment has spread beyond its origin through K-pop and Korean drama cultural influence. For many couples, the 100-day mark represents the transition from early dating uncertainty to established relationship.
This calculator works for any meaningful start date — not just romantic relationships. People use it for friendships, sobriety anniversaries, job start dates, and other significant personal milestones. The purpose is the same: making time visible, and making meaningful moments worth marking.
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