# How to use the RAND function

**What is the RAND function?**

The RAND function calculates a random real number greater than or equal to 0 and less than 1. The function is volatile.

**What is random?**

Each outcome of a random process cannot be predicted with certainty before it occurs. It is unpredictable.

**Is the RAND function random?**

No, it is pseudo-random. The generated value is not truly random.

**What is pseudo-random?**

Random numbers created by software like Excel are not truly random, they can be predicted. That is why they are called pseudo-random meaning they look like random values but they are not.

**What is volatile?**

The function is volatile meaning a new random real number is returned every time the worksheet is calculated.

**What is the effect of volatile functions?**

They may slow down your worksheet/workbook if you have many volatile functions.

**When is the worksheet calculated?**

Cells containing non volatile functions are only calculated once or until you force a recalculation, however, volatile functions are recalculated each time you type in a cell and press enter.

**Can you stop recalculating a worksheet?**

Yes, you can change a setting to manual recalculations.

- Go to tab "Formulas".
- Press with left mouse button on the "Calculation Options" button, a popup menu appears.
- Press with mouse on "Manual".

This stops the automatic recalculations.

**How to force a recalculation?**

Pressing F9 key will recalculate or refresh all the formulas and values in every worksheet of every workbook you have open.

Pressing Shift+F9 will only recalculate the formulas and values on the single worksheet you're currently viewing or active.

Pressing Ctrl+Alt+F9 is the quickest way to force a full recalculation of absolutely everything in all open workbooks, even if nothing has changed. It ignores whether changes were made or not and completely recomputes.

**Are there more volatile functions in Excel?**

Yes. OFFSET, TODAY, NOW among others.

Function | Syntax | Description |
---|---|---|

OFFSET | OFFSET(reference, rows, cols) | Returns a cell offset from a reference cell. |

TODAY | TODAY() | Returns the current date. |

NOW | NOW() | Returns current date and time. |

RANDARRAY | RANDARRAY([rows], [columns], [min], [max], [whole_number]) |
Returns an array with random numbers. |

RANDBETWEEN | RANDBETWEEN(bottom, top) | Returns a random whole number between bottom and top |

Note, that conditional formatting is extremely volatile or super-volatile meaning it is recalculated as you scroll through a worksheet.

**What other functions return random values?**

Excel Function | Syntax | Description |
---|---|---|

RAND() | RAND() | Returns a random decimal number between 0 and 1 |

RANDBETWEEN | RANDBETWEEN(bottom, top) | Returns a random whole number between bottom and top |

RANDARRAY | RANDARRAY([rows], [columns], [min], [max], [whole_number]) |
Returns an array with random numbers. |

### RAND function Syntax

RAND()

### RAND function Arguments

The RAND function has no arguments.

### RAND function example

Formula in cell B3:

### Generate random integers

### Generate random values in a given range

### 'RAND' function examples

The RAND() function In Excel returns a number greater than or equal to 0 (zero) and less than 1. Combining […]

Microsoft Excel has three useful functions for generating random numbers, the RAND, RANDBETWEEN, and the RANDARRAY functions. The RAND function […]

### Functions in 'Math and trigonometry' category

The RAND function function is one of 73 functions in the 'Math and trigonometry' category.

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