How to use the ROUND function
What is the ROUND function?
The ROUND function calculates a rounded number based on the number of digits you specify.
Table of Contents
1. Introduction
How to round numbers?
Rounding is a method to simplify a number by reducing its digits while keeping its approximate value close to the original value.
There are a few common ways to round:
- Round to a set number of decimal places, rounding 2.13579 to 2 decimal places gives 2.14.
- Round up or down to the nearest integer, rounding up 2.3 gives 3. Rounding down 2.3 gives 2.
- Round to a set increment, rounding to the nearest 10 rounds 17 to 20.
- Round to significant figures, rounding 2.333 to 3 significant figures gives 2.33.
When rounding, look at the first digit after where you want to round. If it's 5 or more, round up. If less than 5, round down. Rounding makes numbers cleaner and easier to work with in many everyday situations, however, they may also cause rounding errors like rounded values can compound errors. Rounding measurements and constants may reduces precision. It is better to round numbers after performing calculations than before.
What is a decimal place?
A decimal place refers to each position held by a digit in a number. The first decimal place is the tenths place (1/10), the second is the hundreds place (1/100) and so on.
What is a comma?
Commas are frequently used in large numbers to help read and interpret the values easier. Commas separate thousands place values in large numbers. For example:
- 10,000 - ten thousand
- 100,000 - one hundred thousand
- 1,000,000 - one million
The comma creates groups of three digits, making it easier to count the zeroes and understand the scale.
In decimal numbers with both whole and fractional parts, commas separate the whole number groups of three digits. For example:
- 3,421.256
- 102,734,221.985
What is an integer?
An integer is a whole number that can be positive, negative, or zero, but not a fraction or decimal.
What other Excel functions round numbers?
| ROUND | Rounds a number to a specified number of digits |
| ROUNDUP | Rounds a number up, away from zero |
| ROUNDDOWN | Rounds a number down, towards zero |
| MROUND | Rounds a number to the nearest multiple of a specified value |
| CEILING | Rounds a number up to its nearest multiple. |
| ODD | Returns number rounded up to the nearest odd integer. |
| EVEN | Rounds a number up to the nearest even whole number. |
| FIXED | Rounds a number to the specified number of decimals, lets you ignore comma separators. |
1. Syntax
ROUND(number, num_digits)
| number | Required. The value to round. |
| num_digits | Required. A number representing the digit you want to round down to. |
3. Example 1
The ROUND function takes two arguments: the number to round and the number of digits to round to. Positive digits round to decimal places, 0 rounds to whole numbers, and negative digits round to tens, hundreds, thousands, etc.
Formula in cell D3:
- number = 11.3
- digits = 0
The function in cell D3 rounds 11.3 to the nearest whole number (0 decimal places) which is 11.
Formula in cell D4:
- number = 11.7
- digits = 0
The function in cell D4 rounds 11.3 to the nearest whole number (0 decimal places) which is 12.
How to round a number to one decimal places?
Formula in cell D5:
- number = 11.3
- digits = 1
The function in cell D5 rounds 11.3 to 1 decimal places which is 11.3.
Formula in cell D6:
- number = 11.7
- digits = 1
The function in cell D6 rounds 11.7 to 1 decimal places which is 11.7.
Formula in cell D7:
- number = 11.39
- digits = 1
The function in cell D7 rounds 11.39 to 1 decimal places which is 11.4.
Formula in cell D8:
- number = 11.32
- digits = 1
The function in cell D8 rounds 11.32 to 1 decimal places which is 11.3.
Formula in cell D9:
- number = 11.35
- digits = 1
The function in cell D9 rounds 11.35 to 1 decimal places which is 11.4.
How to round a number to the nearest whole number?
Formula in cell D10:
- number = -1.2
- digits = 0
The function in cell D10 rounds -1.2 to 1 decimal places which is -1.
Formula in cell D11:
- number = -1.9
- digits = 0
The function in cell D11 rounds -1.9 to 1 decimal places which is -2.
How to round a number to the nearest multiple of 10?
Formula in cell D12:
- number = 111
- digits = -1
The function in cell D12 rounds 111 to -1 digits which rounds the value to tens. In this case: 110.
How to round a number to the nearest multiple of 100?
Formula in cell D13:
- number = 111
- digits = -2
The function in cell D13 rounds 111 to -2 digits meaning rounding the value to hundreds. In this case: 100.
How to round a number to the nearest multiple of 1000?
Formula in cell D14:
- number = 111
- digits = -3
The function in cell D14 rounds 111 to -3 digits meaning rounding the value to thousands. In this case: 0. 111 is closer to 0(zero) than 1000.
4. Example 2
What is the hypotenuse in a right triangle if the opposite side is 6 units and the adjacent side is 7 units? Round the value to one decimal.
What we know from this question:
- Right triangle. We can use Pythagoras theorem to calculate the hypotenuse: c2 = a2 + b2
It states that the squared hypotenuse is equal to the sum of the squared opposite side and the squared adjacent side. - Opposite length (a): 6 units
- Adjacent length (b): 7 units
c2 = a2 + b2
c = √(a2 + b2)
Formula in cell C20:
Here is, basically, how the formula works:
- Square the opposite side a2 = 62 = 36
- Square the adjacent side b2 = 72 = 49
- Add the squared opposite and the squared adjacent lengths. 36 + 49 = 85
- Calculate the square root of the sum. √85 = 9.21954445
- Round the result to one decimal. 9.21954445 rounded to one decimal is 9.2
Explaining formula in cell C20
Step 1 - Square the opposite side (b)
The caret character allows you to raise a number to the power of n. The opposite side is 6 units. The caret character followed by number 2 lets you square a given number.
6^2 = 6 * 6 = 36
Step 2 - Square the adjacent side (a)
The adjacent side is 7 units.
7^2 = 7 * 7 = 49
Step 3 - Add the squared values
The plus sign lets you add values in an Excel formula.
36 + 49 = 85
Step 4 - Calculate the square root of the total
The POWER function calculates a number raised to a power.
Function syntax: POWER(number, power)
I am using the POWER function to calculate the square root, however, you can use the caret character as well. The SQRT function works also fine. It is up to you.
POWER(6^2+7^2,0.5)
becomes
POWER(85,0.5) and returns 9.21954445729289
Step 5 - Round the result to 1 decimal
ROUND(POWER(6^2+7^2,0.5),1)
becomes
ROUND(9.21954445729289,1) and returns 9.2
'ROUND' function examples
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Functions in 'Math and trigonometry' category
The ROUND function function is one of 63 functions in the 'Math and trigonometry' category.
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