How to Generate Random Number in a Range with Excel VBA

Not only in Excel VBA but also while working with almost all the programming languages, we often need to generate one or more random number (s) in between a range. In this article, I’ll show you how you can generate random numbers in a range with examples including both repetition and not repetition.

Generate a Random Number in a Range with Excel VBA (Quick View)

Sub Random_Numbers_with_Rnd()

Bottom = 11
Top = 20
Random_Number = Application.WorksheetFunction.RandBetween(Bottom, Top)

End Sub

How to Generate Random Numbers in a Range with Excel VBA: 2 Methods

There are 2 methods available to generate a random number in a range with Excel VBA.

1. Generate a Random Number in a Range with the Excel RandBetween Function in VBA

First of all, we’ll generate random numbers within a range using the RandBetween function of Excel in VBA.

The syntax of the RandBetween function is very simple.

It takes two number arguments called bottom and top and generates a random number between them, including them.

Therefore, to generate a random number between 1 and 100, the VBA code will be:

⧭ VBA Code:

Sub Random_Numbers_with_RandBetween()

Bottom = 11
Top = 20
Random_Number = Application.WorksheetFunction.RandBetween(Bottom, Top)

End Sub

⧭ Output:

Run the code after inserting an extra line MsgBox Random_Number.

It’ll display a random number between 11 and 20.

2. Generate a Random Number in a Range with VBA Rnd Function

Now, we’ll generate random numbers within a range using the VBA Rnd function.

The syntax of the Rnd function is:

It generates a random number between 0 and 1.

To generate a random number between 1 and 100, the VBA code will be:

⧭ VBA Code:

Sub Random_Numbers_with_Rnd()

Bottom = 11
Top = 20
Random_Number = Bottom + Int(Rnd() * (Top - Bottom + 1))

End Sub

⧭ Output:

Again run the code after inserting an extra line MsgBox Random_Number.

It’ll display a random number between 11 and 20.

Generating Random Numbers in a Range with Repetition

Here we’ve got a data set with the names of 10 students in a school.

There are 10 teams in the school consisting of numbers between 1 to 10. We need to assign each student to any of the 10 teams available randomly.

Therefore, we need to generate a series of random numbers between 1 to 10 in the range C4:C13 of the worksheet.

There may be more than one student in one group. So there may be repetitions.

We can accomplish this using both the RandBetween function and the Rnd function. But we’ll use the RandBetween function here.

If you wish, you can try the Rnd function on your own.

The VBA code with the RandBetween function will be:

⧭ VBA Code:

Sub Random_Numbers_with_Repetition()

Set Rng = Range("C4:C13")

Bottom = 1
Top = 10

For i = 1 To Rng.Rows.Count
    For j = 1 To Rng.Columns.Count
        Rng.Cells(i, j) = Application.WorksheetFunction.RandBetween(Bottom, Top)
    Next j
Next i

End Sub

⧭ Output:

Run this code. It’ll create a series of random numbers from 1 to 10 in the range C4:C13 of the worksheet with repetition.

Read More: How to Generate Random Number with Excel VBA

Generating Random Numbers in a Range without Repetition

Now, we’ll assign each student a unique team. That means we’ll generate a series of random numbers between 1 to 10 in the range C4:C13, this time without repetition.

We’ll use the Rnd function of VBA here.

⧭ VBA Code:

Sub Random_Numbers_without_Repetition()

Set Rng = Range("C4:C13")

Bottom = 1
Top = 10

Dim Numebrs() As Variant
ReDim Numbers(Top - Bottom)

For i = LBound(Numbers) To UBound(Numbers)
    Numbers(i) = Bottom + i
Next i

For i = 1 To Rng.Rows.Count
    For j = 1 To Rng.Columns.Count
        Index = LBound(Numbers) + Int(Rnd() * (UBound(Numbers) - LBound(Numbers) + 1))
        Rng.Cells(i, j) = Numbers(Index)
        For k = Index To UBound(Numbers) - 1
            Numbers(k) = Numbers(k + 1)
        Next k
        If UBound(Numbers) <> 0 Then
            ReDim Preserve Numbers(UBound(Numbers) - 1)
        End If
    Next j
Next i

End Sub

⧭ Output:

Run this code. It’ll create a series of random numbers from 1 to 10 in the range C4:C13 of the worksheet without repetition.

Things to Remember

The Rnd function is a function of VBA. That’s why we used it directly in our codes. On the other hand, the RandBetween function is not a VBA function, it’s actually an Excel function. That’s why we had to use it along with the Application.WorksheetFunction property.

Download Practice Workbook

Download this practice workbook to exercise while you are reading this article.

Conclusion

So, these are the ways to generate random numbers in a range using VBA in Excel. Do you have any questions? Feel free to ask us. Don’t forget to visit our site ExcelDemy for more posts and updates.

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