Excel Random Number Generation
This page gives examples of use of the Excel random number generation functions to perform the following random selections:
| Select a Random Decimal Value Between 0 and 1 |
| Select a Random Integer Between Two Supplied Integers |
| Select a Random Decimal Between Two Specified Numbers |
| Select a Random Value From a List |
Select a Random Decimal Value Between 0 and 1
If you want to generate a random decimal value between 0 and 1, simply used the Excel Rand function in any cell of your worksheet:
=RAND()
This function will generate a different random decimal, between 0 and 1 every time your worksheet re-calculates.
Select a Random Integer Between Two Supplied Integers
The Excel Randbetween function is used to generate a random integer between two supplied integers. For example:
=RANDBETWEEN( 0, 10 )
generates a random integer between 0 and 10.
Select a Random Decimal Between Two Specified Numbers
If you want to generate a random decimal value between any two values, A and B the following formula (which used the Excel Rand function) can be used:
=A+(B-A)*RAND()
Example 1
The following formula generates a random decimal value between the values 5 and 10:
=5+(10-5)*RAND()
Example 2
The formula below generates a random decimal value between the values 0.5 and 1.2:
=0.5+(1.2-0.5)*RAND()
Select a Random Value From a List
| A | |
|---|---|
| 1 | Adam |
| 2 | Bill |
| 3 | Colin |
| 4 | Harry |
| 5 | John |
| 6 | Ken |
| 7 | Lee |
| 8 | Mike |
If you want to select a value at random from a list, this can be done with the use of the Excel Randbetween, Counta and Index functions.
For example, if you want to select a name at random from the values In cells A1 - A8 of the spreadsheet on the right, this can be done using the following formula:
=INDEX( A1:A8, RANDBETWEEN( 1, COUNTA( A1:A8 ) ) )
In the above formula:
- The Counta function returns the number of non-blank cells in the range A1 - A8, (which, in this example, equates to the value 8).
- The Randbetween function returns a random integer between 1 and 8.
- The Index function returns a reference to the n'th cell in the range A1 - A8 (where n is the random integer returned by the Randbetween function)
Note that the Excel Rand and Randbetween functions return different values every time the spreadsheet recalculates. To force a recalculation at any time, press the F9 key.