Today is February 29, 2024. Since 2024 is a leap year, it has 29 days in February. This means that as of today, we are already in the 60th day of the year.

Here's how to calculate the number of years that have passed since 2018:

Calculate the number of days from January 1, 2024, to today: February 29, 2024 - January 1, 2024 = 59 days.

Subtract the number of days from the total number of days in 2023: 365 days (in a non-leap year) - 59 days = 306 days.

Subtract the number of days in 2023 from the total number of days since 2018:

Since 2020 was a leap year, the total number of days from 2019 to 2023 is: (4 normal years * 365 days/year) + 1 leap year * 366 days/year = 1461 days + 366 days = 1827 days.

Subtract the days from 2023: 1827 days - 306 days = 1521 days.

Divide the remaining days by the number of days in a year (365) to get the number of years: 1521 days / 365 days/year ≈ 4.17 years.

Therefore, as of today, it has been approximately 4.17 years since 2018. It's important to note that this answer is an approximation, and the exact number of years will depend on the specific date you consider within 2024.