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**16 October 2018**** minus 28 days** will be

18th September 2018

For example

- What is 20 days from Today? (Today plus 20 days)
- What is 800 months from 1 March 2024? (1 March 2024 plus 800 months)
- What is 21 weeks before Yesterday? (Yesterday minus 21 weeks)
- What is 400 months from 9 February 2021? (9 February 2021 plus 400 months)
- What is 7 years before Tomorrow? (Tomorrow minus 7 years)
- What is 500 years before 5 May 2025? (5 May 2025 minus 500 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.