Number of days between October 1st, 2020 and April 13th, 2021
The total number of days between Thursday, October 1st, 2020 and Tuesday, April 13th, 2021 is 194 days.
This is equal to 6 months and 12 days.
This does not include the end date, so it's accurate if you're measuring your age in days, or the total days between the start and end date. But if you want the duration of an event that includes both the starting date and the ending date, then it would actually be 195 days.