How Old Is It? Anniversary & Years-Elapsed Calculator

Find the number of years (the anniversary) from a founding, establishment or birth year to a reference year. Enter a Gregorian or Japanese-era year and instantly see the next 10-year milestone.

Input

How to enter the starting year (founding, establishment or birth)

Starting year (CE)

Reference year (the year to measure to; defaults to this year)

Result

Enter a starting year and a reference year.

How it works

Years elapsed (the anniversary) are calculated as "reference year − starting year." A business founded in 2000, for example, reaches its 25th anniversary in 2025.
The starting year can be entered as a Gregorian (CE) year or a Japanese-era year. For the era format, pick the era name and the year within that era.
The reference year defaults to the current year, but you can freely change it to any past or future year.
Both the Japanese-era and the CE form of the starting year are shown, which helps when checking how to phrase a company history or announcement.
It also shows the CE year of the next milestone (10th, 20th anniversary and so on) and how many years remain until then.
If you need an exact anniversary or day count that includes the month and day, use this alongside our birthday and elapsed-days tools.

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