Figuring out what time it was in the past is a pretty common task. Whether it’s scheduling a meeting, trying to remember when something happened, or just plain curiosity, time calculations come up more than you think.
So, what time was it 21 minutes ago? There are a few ways to find out, from doing the math in your head to using a handy online tool.
How to calculate what time it was 21 minutes ago
Let’s say you don’t have a handy dandy online calculator, and you need to figure out what time it was 21 minutes ago. Here’s how you’d do it by hand.
Figuring out the current time
First, you need to know the time now. Write it down as HH:MM. You’ll also need today’s date (Day, Month, Year), in case you have to subtract from the hour or even go back to the previous day.
Subtracting 21 minutes
Subtract 21 minutes from the current minute. If the result is a positive number, you’re good to go — the hour stays the same. If the result is a negative number, you’ll need to borrow an hour (60 minutes) from the hour value. If borrowing that hour makes the hour a negative number, you’ll need to adjust the date to yesterday’s date.
Online “Minutes Ago” Calculators
Figuring out the time and date from a certain number of minutes in the past can be tricky, but luckily, there are a number of free online calculators that can do the work for you.
These calculators take the number of minutes as an input and deliver the exact date and time as an output.
How to use a “minutes ago” calculator
Using one of these calculators is usually as simple as finding the input field (it may be labeled “Minutes Ago”) and typing in the number of minutes. As soon as you enter the number of minutes, the calculator will show you the date and time in the past.
Advantages of using a calculator
Calculators are accurate and fast. They don’t make mistakes like you or I might, and they deliver answers instantly, saving you time and effort.
Examples of calculating time 21 minutes ago
Let’s walk through a few examples to show you how to calculate what time it was 21 minutes ago.
Example 1: Current time is 3:45 p.m.
To find out what time it was 21 minutes ago, we simply subtract 21 minutes from 3:45 p.m., which gives us 3:24 p.m. In this case, the date doesn’t change.
Example 2: Current time is 12:10 a.m.
Subtracting 21 minutes from 12:10 a.m. gets a little trickier, because we cross over into the previous day. In this case, 12:10 a.m. minus 21 minutes is 11:49 p.m. of the day before.
Don’t forget the date!
It’s important to remember that the date changes when you’re subtracting minutes and your calculation crosses over into the previous day. If you forget to adjust the date, you won’t have an accurate answer.
Final Thoughts
Whether you subtract 21 minutes from the current time using mental math or an online calculator, you can easily figure out what time it was a short while ago.
Accurate time calculations matter in all sorts of situations, so use whichever method works best for you in the moment.