Date Calculator

Date Calculator

Our Date Calculator calculates the time difference between two dates: a "from" and an “until” date. The result of the calculation returns not only the difference in years, but also in months, weeks and days, to suit different levels of precision.

Calculating the date difference of two events or people, can help in legal things such as age verification, and insurance eligibility. It can also be useful to know how long a relationship has lasted, or to determine fair competitors in youth's sport division. Here, automated date-difference calculations are preferred over manual counting due to its accuracy. Use this tool whenever you need a fast, precise, and reliable way to calculate the difference between two dates.

Calendar Peculiarities

Calculating the date-difference is, in essence, a counting problem. It sounds easier than it is, because of how a year is defined. Namely, one year is defined as the time planet Earth takes to revolve around the sun once. This is approximately 365.25 days, rather than exactly 365 days. To adjust for this small discrepancy, the modern (western) calendar, known as the Gregorian calendar, includes a leap year roughly every four years to keep the calendar aligned with Earth's orbit around the sun. Moreover, even if a year was exactly 365 days, we still encounter the issue that 365 is not divisible by 12 months. If we wanted, we could divide it by 5 months, but then we run into the issue that many holidays and remembrance days have already been culturally established on set dates. Luckily, computers are very the best counting tools we have, and by programming in these peculiarities, it can count the date-difference very fast and accurately.