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**15 October 2018**** minus 100 days** will be

7th July 2018

For example

- What is 900 weeks from Today? (Today plus 900 weeks)
- What is 30 days before 11 February 2026? (11 February 2026 minus 30 days)
- What is 600 weeks from Yesterday? (Yesterday plus 600 weeks)
- What is 25 years before 29 November 2021? (29 November 2021 minus 25 years)
- What is 5 years before Tomorrow? (Tomorrow minus 5 years)
- What is 5 days from 13 April 2023? (13 April 2023 plus 5 days)

The **Gregorian calendar** is the most widely used internationally civil calendar. It is named after Pope Gregory 13th, who introduced it in **October 1582**.

The Gregorian calendar is a **solar calendar**. A regular Gregorian year consists of 365 days, but as in the Julian calendar, in certain years, a leap year, a **leap day is added to February**

The months of **April, June, September, and November** have **30 days**, while the **rest have 31 days** except for **February**, which has **28 days** in a standard year, and **29 in a leap year**.

For best results, please use dates after 1752 and **verify any data** if you are doing genealogy research.