# How long until our next anniversary?

Counts how long you have been married or together in years, months and days, and gives the date of your next anniversary, which one it is and the next milestone.

- Page: https://www.acalculator.org/days/anniversary-calculator
- JSON spec: https://www.acalculator.org/days/anniversary-calculator.json
- Version: d405b49fb67a

## Default answer

Example with the default inputs (Wedding date June 20, 2015, Count from October 5, 2026) on the example date Monday, October 5, 2026: Your 12th anniversary is on Sunday, June 20, 2027, in 258 days.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| start | Wedding date | The date of your wedding, or the day you got together. |
| on | Count from | The date to count from. Today, unless you change it. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| days | Days until the next anniversary | Days from the count-from date to the next anniversary; 0 when it is that day. |
| next | Next anniversary | The date of the next anniversary. |
| which | Which anniversary | The number of the next anniversary. |
| together | Time together | Whole years, months and days from the wedding date to the count-from date. |
| totalDays | Days together | Days from the wedding date to the count-from date. |
| milestone | Next milestone | The next 1st, 5th, 10th or later milestone anniversary on or after the count-from date, with its traditional name. |
| milestoneDate | Milestone date | The date of the next milestone anniversary. |

## Method

next anniversary = the wedding date plus the fewest whole years (at least 1) on or after the count-from date; days until = next − count-from date; time together = whole years, months, days.

## Assumptions

- A February 29 wedding date has its anniversary on February 28 in common years.
- On the anniversary itself the count is 0 and that anniversary is the next one.
- Milestones are the 1st, every 5th up to the 80th, with the traditional names in Wikipedia’s list; names vary by country.

## Worked examples

1. start = 2015-06-20, on = 2026-10-05 gives days = 258, next = 2027-06-20, which = 12th, together = {"years":11,"months":3,"days":15}, totalDays = 4,125, milestone = 15th (crystal), milestoneDate = 2030-06-20. Source: Wikipedia, Wedding anniversary (traditional names: 25th silver, 30th pearl, 40th ruby, 50th gold, 60th diamond), https://en.wikipedia.org/wiki/Wedding_anniversary (retrieved 2026-10-05).
2. start = 2001-10-05, on = 2026-10-05 gives days = 0, which = 25th, milestone = 25th (silver), together = {"years":25,"months":0,"days":0}. Source: Wikipedia, Wedding anniversary (traditional names: 25th silver, 30th pearl, 40th ruby, 50th gold, 60th diamond), https://en.wikipedia.org/wiki/Wedding_anniversary (retrieved 2026-10-05).
3. start = 2004-02-29, on = 2026-03-01 gives days = 364, next = 2027-02-28, which = 23rd, milestone = 25th (silver), milestoneDate = 2029-02-28. Source: U.S. Naval Observatory, Leap Years: the Gregorian leap year rule, https://aa.usno.navy.mil/faq/leap_years (retrieved 2026-10-05); Wikipedia, Wedding anniversary (traditional names: 25th silver, 30th pearl, 40th ruby, 50th gold, 60th diamond), https://en.wikipedia.org/wiki/Wedding_anniversary (retrieved 2026-10-05).

## FAQ

### How do I work out which anniversary is next?

Subtract the wedding year from this year. If this year’s anniversary has not come yet, that is the next one; if it has passed, add 1. A June 20, 2015 wedding has its 12th anniversary on June 20, 2027 when counted from October 2026.

### How long have we been married?

Count whole years from the wedding date, then whole months, then days. From June 20, 2015 to October 5, 2026 is 11 years, 3 months and 15 days, or 4,125 days.

### When is the anniversary of a February 29 wedding?

In leap years on February 29. In other years this page uses February 28, the last day of February.

### What are the milestone anniversaries?

The 1st (paper), 5th (wood), 10th (tin), 15th (crystal), 20th (china), 25th (silver), 30th (pearl), 40th (ruby), 50th (gold) and 60th (diamond) are the best known. The page shows every fifth year up to the 80th (oak).

### Is today our anniversary?

If the count shows 0 days, yes: the next anniversary is today, and its number is the one you are celebrating.

## Sources

- Wikipedia, Wedding anniversary: the traditional names of anniversaries. https://en.wikipedia.org/wiki/Wedding_anniversary (retrieved 2026-10-05)
- U.S. Naval Observatory, Leap Years: the Gregorian leap year rule. https://aa.usno.navy.mil/faq/leap_years (retrieved 2026-10-05)