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**21 October 2018**** minus 45 days** will be

6th September 2018

For example

- What is 20 months from Today? (Today plus 20 months)
- What is 40 months before 12 March 2023? (12 March 2023 minus 40 months)
- What is 28 days before Yesterday? (Yesterday minus 28 days)
- What is 400 weeks before 8 February 2024? (8 February 2024 minus 400 weeks)
- What is 4 weeks before Tomorrow? (Tomorrow minus 4 weeks)
- What is 25 years before 12 August 2024? (12 August 2024 minus 25 years)

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.