Adding Hours Calculator
Our adding hours calculator will help you add the time required to complete different tasks. Knowing how long it takes to perform a task will help you schedule your day better and meet your daily goals efficiently. Whether you wish to find the time it takes to complete different jobs or you're just adding work hours, this calculator has your back! ⏲️
In the following article, we shall see how you can effectively use this calculator to add hours with an example. We shall also see how you can subtract hours! 😉
Using our adding hours calculator
Say you are taking half a day off on Monday to go to the bank. It will take you half an hour to get to the bank, an hour and a half to conclude your business there, and another 90 minutes to get some lunch and reach your office. Let's use our userfriendly adding hours calculator to find out how long the entire venture is going to take:

In the first field, enter 0.5 hours. Alternatively, you can change the units to minutes and input 30 mins.

In the second field, input 1.5 hours. Remember, you can choose a different unit that you find comfortable.

Because you used two input fields, our adding hours calculator will now generate a third input field. It can generate up to 20 input rows on demand.

In the third field, enter 1.5 hours.

In the field result's units, choose which unit you wish the result to be displayed in. The default setting is hours.

The calculator will add your inputs to give the result: 4 h.
🙋 Wait!! Isn't 0.5 + 1.5 + 1.5 = 3.5
? Why does the calculator say 4 h? This is because our calculator is rounding the answer up! You can change the result units to hours/minutes to get more accurate answers! Then, it'll show you the proper answer: 3 h 30 min.
"Negative" time: Adding and subtracting hours calculation
Have you noticed that our calculator allows negative time inputs? Why did we do that? Time is a scalar quantity; It cannot be negative. But, using negative input values, you can subtract time! This is helpful in some cases, for example, to see if you can complete some tasks in a given time.
Let's continue with our previous example. When you leave home for the bank, if your boss calls you and says he needs you in the office in 4 hours, how do you know if 4 hours is enough to conclude your tasks at the bank and get to the office?

In the first field, enter the time allowed to complete your tasks: 4 hours.

In the second field, enter the time it'll take you to go to the bank: 0.5 hours. But ensure your entry is negative: 0.5 hours.

Repeat Step 2 to input negative values of the time taken to complete all other tasks before you reach the office: 1.5 hours and 1.5 hours.

The calculator will subtract hours to give you the result: 1 hour. For a more accurate answer, switch the result's units to hours/minutes. This will give you 30 minutes.
Thus, you know you have enough time to comfortably complete your tasks and reach your office with 30 minutes to spare! 😉 Note that:
 If the result were 0 hours and 0 minutes, it would mean you would be right on time; but
 If the result was a negative value, you would be running late, because you would be using time that isn't there.
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FAQ
How do I add 42 hours and 210 mins?
The sum of 42 hours and 210 mins gives us 45 hours and 30 minutes. To arrive at this answer, follow these steps:

Divide 210 minutes by 60 minutes to convert it into hours:
210/60 = 3.5 hours
. 
Add 42 hours with 3.5 hours to get:
42 + 3.5 = 45.5 hours
. This is equivalent to 45 hours 30 minutes. 
Verify with our adding hours calculator.
What was the first timekeeping device?
The earliest known timekeeping device is the sundial, which uses a light spot or a shadow cast by the Sun to determine local solar time. The oldest known sundials are from 1500 BC, discovered in The Valley of Kings in Egypt.