Relationship Anniversary Calculator
Enter your relationship start date to see how many days you have been together and when your next day milestone and yearly anniversary will occur.
Last updated: July 2026
Your result
Next 100-day milestone
Next anniversary
Selected day milestones
Milestones relative to the calculate-as-of date.
| Milestone | Date | Status |
|---|
Selected anniversaries
Yearly milestones for your shared journey.
| Anniversary | Date | Status |
|---|
Relationship days are counted from the start date as Day 1. UTC date-only math keeps the result stable across time zones and daylight-saving shifts.
What this calculator tells you
Use this tool to see your current relationship day number, completed full days, weeks, your exact calendar duration, and the next round-number day milestone and calendar anniversary.
How relationship days are counted
Your start date is counted as Day 1. Completed days are one less than your current relationship day number.
Day milestones and yearly anniversaries
The calculator highlights key day milestones such as 100, 365, 500, 1,000, 2,000, 5,000, and 10,000 days, along with yearly anniversaries such as 1, 2, 3, 5, 10, and 25 years.
Worked example
For a relationship that started on November 1, 2023 and a calculate-as-of date of July 27, 2026, the relationship is on Day 1,000, with 999 full days completed. The exact duration is 2 years, 8 months, and 26 days, the next 100-day milestone is Day 1,100, and the next anniversary is the 3rd anniversary on November 1, 2026.
Frequently asked questions
Is the relationship start date counted as Day 1?
Yes. The calculator uses the relationship start date as Day 1, so your current day number is completed days plus one.
What is the difference between a 365-day milestone and a yearly anniversary?
Day milestones count calendar days from the start date, while anniversaries count calendar years from the start date.
What happens if the relationship began on February 29?
In non-leap years, the calendar anniversary uses February 28 to keep the anniversary on a real calendar date.
Can I calculate milestones for friendships, sobriety, projects, or other journeys?
Yes. The same logic works for any shared timeline where you want to understand progress and upcoming milestones.
Why might another calculator differ by one day?
Some tools use local time or treat the start date as Day 0 instead of Day 1. This calculator uses UTC date-only arithmetic to keep results consistent.