Please Note: This article is written for users of the following Microsoft Excel versions: 2007, 2010, and 2013. If you are using an earlier version (Excel 2003 or earlier), this tip may not work for you. For a version of this tip written specifically for earlier versions of Excel, click here: Rounding to Two Significant Digits.

Rounding to Two Significant Digits

by Allen Wyatt
(last updated August 23, 2014)

3

Tammy needs to round values in a worksheet to two significant digits. For instance, if a cell contains 137, it should round to 140; if it contains 0.0005937 it should round to 0.00059; and if it contains 156735.32 it should round to 160000. She wonders if there is a simple formula to round any given number to only two significant digits.

Of course, it depends on what your definition of "simple" is. Fact of the matter, though, is that there are several different formulas you can use to get the desired result. Assuming that your original value is in cell A1, you can use any of the following representative formulas:

=ROUND(A1/(10^(INT(LOG10(ABS(A1)))+1)),2)*(10^(INT(LOG10(ABS(A1)))+1))
=ROUND(A1,-(INT(LOG(ABS(A1),10))+1)+2)
=FIXED(A1,1-INT(LOG10(ABS(A1))))
=ROUND(A1,1-INT(LOG(ABS(A1))))

These formulas will work with either positive or negative values just fine. The LOG (or LOG10) function is used to determine the number of digits either to the left or right of the decimal place before the first significant digit occurs. The INT of that function actually provides a number that is one less than the number of digits required, so that is why the value has 1 added to it. We can then round using that number of digits.

If you think that you may want to use a different number of significant digits than two, then you can use either of the following formulas:

=ROUND(A1,2-INT(LOG(ABS(A1)))+1)
=ROUND(A1,2-INT(LOG10(ABS(A1)))+1)
=FIXED(A1,2-INT(LOG10(ABS(A1)))-1)

All you need to do is change the 2 to reflect any number of significant digits you want. More information about significant digits in Excel can be found here:

http://excelribbon.tips.net/T012083

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (10397) applies to Microsoft Excel 2007, 2010, and 2013. You can find a version of this tip for the older menu interface of Excel here: Rounding to Two Significant Digits.

Author Bio

Allen Wyatt

With more than 50 non-fiction books and numerous magazine articles to his credit, Allen Wyatt is an internationally recognized author. He  is president of Sharon Parq Associates, a computer and publishing services company. ...

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Comments

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What is six less than 6?

2015-08-06 08:18:13

MIchael Armstrong

A slightly more elegant, if not more obscure, formula comes to mind; don't know which of my suggestions is the faster:

=IF(MOD(A1*100,1)=0.5,A1,ROUND(A1,2))

and of course, the cell is formatted to display to 3 decimal places.


2015-08-06 08:07:40

MIchael Armstrong

Here's a very inelegant way to do it; assume the number is in cell A1:

=IF(A1*100-INT(A1*100)=0.5,A1,ROUND(A1,2))


2015-08-06 01:03:41

Mostafa Saqallah

Hi,
Good morning all, hope everything is well!

I'm living in the Middle East "Kuwait" and when we use Microsoft Excel to calculate currencies we use 3 decimals, for example 100.623, 47.187, 249.446, 8075.343, 642.508 Kuwaiti Dinars (KWD).

Is there a way to round to the nearest decimal, as opposed to the nearest dinar.

These are two types of roundings, for example:

Type 1:
Example 1: 54.250 keep it as 54.250
Example 2: 54.251 round to 54.250
Example 3: 54.252 round to 54.250
Example 4: 54.253 round to 54.250
Example 5: 54.254 round to 54.250
Example 6: 54.255 keep it as 54.255

Type 2:
Example 1: 155.375 keep it as 155.375
Example 2: 155.376 round to 155.380
Example 3: 155.377 round to 155.380
Example 4: 155.378 round to 155.380
Example 5: 155.379 round to 155.380
Example 6: 155.380 keep it as 155.375

To make it more clear, for Type 1 decimals (from 1-4) round it to "0".

And for Type 2 decimals (6-9), round it to "1".

If the last decimal is 0 or 5 just keep it as is (e.g. 11.250, 46.895, 425.110, 201.640, 5.115, 25.160, etc.)

Could you please show me how I can use the right formula in Excel without using micro?

Let me know if you need any more clarification.

Best Regards,

Mostafa Saqallah


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