120 months before today was 17 May 2015, a Sunday. Subtracting 120 months in the past is usually just counting from May; however, longer calculations will push us from 2025 into 2024 or further. Even if the calculation remains within the year, I usually take note of the 17 days left in the middle of May to prep for an additional calculation before April. But that’s all there is to it - understand the month, if 120 months will change the year, season, or fiscal calendar, and subtract your dates.
All of our day calculators are measured and QA'd by our engineer. Read more about the Git process here. But here's how 120 months ago gets calculated on each visit:
120 months is Sunday May 17, 2015 or could be if you only want workdays. This calculation takes 120 months and only subtracts by the number of workdays in a week. Remember, removing the weekend from our calculation will drastically change our original Sunday May 17, 2015 date.
Work months Solution
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
120 months back
Sunday
May 17
Counting back from today is Sunday May 17, 2015 using a full calendar, and is also 89280 hours ago and 37.53% of the year.
Sunday Sunday May 17, 2015 was the 137 day of the year. At that time, it was 37.53% through 2015.