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**6 August 2021**** minus 9 years** will be

6th August 2012

For example

- What is 1 week before Today? (Today minus 1 week)
- What is 100 months from 23 July 2025? (23 July 2025 plus 100 months)
- What is 13 days from Yesterday? (Yesterday plus 13 days)
- What is 4 days before 28 August 2023? (28 August 2023 minus 4 days)
- What is 30 days from Tomorrow? (Tomorrow plus 30 days)
- What is 20 years before 18 January 2024? (18 January 2024 minus 20 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.