Every time you enter your date of birth into our calculator, you are benefiting from thousands of years of human ingenuity in measuring time. The story of how we arrived at our modern calendar is a fascinating journey through astronomy, religion, and politics.
One of the earliest known calendars was created by the ancient Egyptians around 3000 BCE. It divided the year into 365 days across 12 months of 30 days each, with five extra days added at the end. This was already remarkably accurate for its time.
In 45 BCE, Julius Caesar introduced the Julian Calendar across the Roman Empire. This system introduced the concept of a leap year every four years, recognising that a solar year is approximately 365.25 days long. It was a major improvement over earlier Roman calendars.
In 1582, Pope Gregory XIII introduced the Gregorian Calendar — the system we use today. It refined the leap year rules further, establishing that century years are only leap years if divisible by 400. This gives an average year of 365.2425 days — remarkably close to the true solar year of 365.2422 days.
Our Age Calculator uses the Gregorian Calendar and accounts for every leap year since your birth date to ensure your age is always perfectly accurate.