Written by Allen Wyatt (last updated March 16, 2024)**This tip applies to** Excel 2007, 2010, 2013, 2016, 2019, Excel in Microsoft 365, and 2021

Ashley wonders how to limit the input of a number to 2 decimal places. In trying to figure it out, she notes that the Data Validation tool does not seem to work for this requirement.

There are two ways you can approach this problem. The first is to use a custom rule in Excel's Data Validation tool. Follow these steps:

- Select the cell where you want to limit the input to two decimal places. (For this example, let's assume you select cell A1.)
- Display the Data tab of the ribbon.
- Click the Data Validation tool. Excel displays the Data Validation dialog box.
- Make sure the Settings tab is displayed. (See Figure 1.)
- In Allow drop-down list, choose Custom.
- In the Formula box (which appears when you complete step 5), enter the following formula:

** Figure 1.** The Settings tab of the Data Validation dialog box.

=MOD(A1*100,1)=0

This validation formula works because it checks to make sure that the value in A1, when multiplied by 100 and then divided by 1, has no remainder. It will only have this remainder if there are three or more decimal places in the value entered. Validation will also fail if someone tries to enter text into cell A1.

There are, of course, any number of other formulas you could use in step 6. Here are a few:

=INT(A1*100)=(A1*100) =A1=ROUND(A1,2) =ABS(A1-ROUND(A1,2))<1E-8 =FIND(".",A1,1)>=LEN(A1)-2

Instead of using Data Validation, there is another approach you could take. This one involves using the following steps:

- Select the cell where you want to limit the input to two decimal places. (For this example, let's assume you select cell A1.)
- Format the cell as desired, but make sure it is at least formatted to display only two decimal places.
- Display the Excel Options dialog box. (In Excel 2007 click the Office button and then click Excel Options. In Excel 2010 and later versions display the File tab of the ribbon and then click Options.)
- Click the Advanced option at the left of the dialog box.
- Scroll through the available options until you see the When Calculating This Workbook section. (See Figure 2.)
- Ensure that the Set Precision as Displayed check box is selected.
- Click OK.

** Figure 2.** The Advanced options of the Excel Options dialog box.

Now, when someone enters a value into the cell you formatted in step 2, it will be rounded to two decimal places automatically, and Excel will make sure that any calculations use the two-decimal-place value.

The drawback to this approach is that changing how Excel does its calculations (steps 3 through 6) affects the entire workbook, not just the data-entry cell selected in step 1. If this is unacceptable to you, then you should definitely choose the Data Validation approach, discussed earlier.

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This tip (889) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, Excel in Microsoft 365, and 2021.

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2024-03-22 12:47:36

J. Woolley

See https://sites.google.com/view/MyExcelToolbox/

2024-03-21 18:04:48

J. Woolley

Public Function Modulo(Number As Double, Divisor As Double) As Double

Modulo = Number - Divisor * WorksheetFunction.Floor(Number / Divisor, 1)

If Abs(Modulo) < 0.0000000001 Then Modulo = 0

End Function

It solves the floating-point residual problem by returning 0 if its absolute value is less than 1.E-10. And it doesn't have the problems mentioned by Tomek where MOD returns 1 or 10 when the result should be 0.

For more on this subject, see the following:

https://stackoverflow.com/a/17525046/10172433

https://en.wikipedia.org/wiki/Modulo

2024-03-19 00:56:03

Tomek

=FIND(".",A1,1)>=LEN(A1)-2

incorrectly identifies whole numbers as not satisfying the condition, even if the cell is formatted to show two decimals, or even when you enter a number like 4.00. The underlying value does not have a decimal point, so it cannot be found.

2024-03-19 00:29:28

Tomek

MOD(A1*1000,10) does not work either. For example if the cell A1 contains 8.05,

=MOD(A1*1000,10) returns 9.09495E-13

=MOD(A1*100,1) returns 1.13687E-13

This is so, even if you enter =Mod(8.05*1000,10) instead of referring to a cell.

Even worse MOD(8.11*1000, 10) returns 10 (!) Of course this is not 10 but a number that differs from 10 by a very small value and is rounded up, but because it is less than 10, it is treated as a reminder from division by 10.

Similarly MOD(8.29*100,1) returns 1.

You are right that this must be rounding error from floating-point arithmetic. The question is how to account for this.

First I thought that formula =MOD(A1*100,10) < 1E-12 could work, but it would still be wrong for MOD(8.29*100,1) as it returns 1.

Possibly a more complicated formula could be used, like =OR(MOD(A2*100,1)<0.000000000001,1-(MOD(A2*100,1)<0.000000000001)), and would do the trick. It did work in my limited testing.

Note: I did make sure that the series of numbers I tested were actually up to two decimal digits, and did not have more digits hidden due to rounding. Such thing happened, when i tried to generate a series of numbers by a formula, or even by filing a range of cells using series option, even after I copied the cells and then pasted them as values. The explicit calculation, or calculation done by excel when filling a series simply accumulates the rounding errors. First, I fell into that trap and almost all my numbers caused the original formula to fail. In this case "What You See Is Not What You Get" WYSINWYG

When I have more time I will check your VBA suggestion. I also did not check the remaining formulas from the tip.

2024-03-18 15:00:12

J. Woolley

Thank you for identifying a problem with Excel's MOD function using the formula MOD(A1*100,1). I believe the problem results unavoidably from floating-point arithmetic. Curiously, MOD(A1*1000,10) seems to work as desired, but MOD(A1*10000,100) does not.

Apparently Excel's MOD function returns the floating-point result of this:

MOD(Number, Divisor) = Number - Divisor*INT(Number/Divisor)

VBA's Mod operator appears to round its parameters with fixed-point result:

Number Mod Divisor =

Round(Number) - Round(Divisor)*Int(Round(Number)/Round(Divisor))

Therefore, the following function does not produce the same result as MOD:

Function ModVBA(Number, Divisor)

ModVBA = Number Mod Divisor

End Function

Conclusion: Be careful when using either function.

2024-03-16 16:41:17

R. A. Williams

OK Invalid OK Invalid OK Invalid OK Invalid OK Invalid

4.55 4.56 4.57 4.56 4.5 4.6 4.62 4.61 4.63 4.64

OK Invalid OK Invalid OK Invalid OK Invalid OK Invalid

4.66 4.65 4.68 4.69 4.76 4.77 4.80 4.81 4.84 4.85

OK Invalid OK Invalid OK Invalid OK Invalid OK Invalid

4.87 4.86 4.88 4.89 4.91 4.90 4.93 4.94 4.97 4.98

A few other invalid values found: 5.02, 5.06, 5.1, 5.11 and 4.1, 4.11, 4.14, 4.15, 4.19, 4.4.

Am I going crazy? Looked a bit outside of the ranges noted above; all looked good. And none of the other four formulae you suggested display this phenomenon. Checked a few negative values; they all follow the pattern for positive values.

I don't have an easy way to validate these bizarre observations and can't think of what to blame them on. If you can try it out and confirm or deny, I would be very interested! (I hate it when shit like this happens!)

Thanks,

Bob Williams

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