# How to Generate Random Numbers Without Duplicates in Excel Using Formulas?

Are you looking for a way to **generate random numbers in Excel without any duplicates**? Excel provides several formulas and functions that allow you to easily create a list of unique random numbers. Generating random numbers is a common task in various scenarios, such as data sampling, creating test data, randomizing lists, and more. However, ensuring that the generated numbers are unique and don’t contain any duplicates can be a bit tricky. In this article, we’ll explain step-by-step how to use Excel formulas to **randomly generate numbers with no duplicates**.

## Understanding Random Number Generation in Excel

Before diving into the formulas to generate random numbers without duplicates, let’s first understand how Excel handles randomness.

Excel provides two key functions for generating random numbers:

**RAND()**: This function generates a random decimal number between 0 and 1. Each time the worksheet is calculated, RAND() produces a new random number. It’s important to note that RAND() does not take any arguments, so you cannot specify a range for the generated numbers.**RANDBETWEEN(bottom, top)**: This function generates a random integer between the specified bottom and top numbers, inclusive. Like RAND(), it generates a new value each time the worksheet is calculated. With RANDBETWEEN(), you have more control over the range of the generated numbers.

While these functions are useful for generating random numbers, they do not guarantee the exclusion of duplicates. If you generate a large enough set of random numbers using these functions, you are likely to encounter repeats. This is because each invocation of RAND() or RANDBETWEEN() is independent and does not consider the previously generated values.

## Using RAND() and RANK() to Generate Random Numbers Without Duplicates

One effective method to **generate a list of random numbers with no duplicates** is to combine the RAND() function with the RANK() function. The RAND() function will generate the random numbers, while the RANK() function will help ensure uniqueness. Here’s how it works:

- In cell A1, enter a header like “Random Number” to label the column where the random numbers will be generated.
- In cell A2, enter the formula: =RAND() This will generate a random decimal number between 0 and 1.
- Copy the formula down to as many cells as the number of random values you want to generate. For example, if you want to generate 100 random numbers, copy the formula down to cell A101.
- In cell B1, enter a header like “Unique Ranking” to label the column where the unique ranking will be assigned.
- In cell B2, enter the formula: =RANK(A2,$A$2:$A$101) This formula assigns a unique rank to each random number based on its position when sorted ascendingly. The RANK() function compares the value in A2 with the range $A$2:$A$101 and returns its rank within that range.
- Copy the formula in B2 down to cell B101 (or however many numbers you are generating). Each cell in column B will now contain a unique ranking for the corresponding random number in column A.
- Select cells B2:B101, copy them, and then paste as values to convert the formulas to static numbers. This step is necessary because the RANK() function will recalculate the rankings whenever the worksheet is updated, which can disrupt the uniqueness of the results.
- Sort column B in ascending order to
**generate your list of random numbers without duplicates**. The unique rankings assigned by the RANK() function will ensure that each random number appears only once in the sorted list.

Here’s what the formulas and results will look like:

Random Number | Unique Ranking |
---|---|

0.749020162 | 92 |

0.441365041 | 27 |

0.551163444 | 53 |

0.201837257 | 4 |

0.853282331 | 98 |

… | … |

By combining RAND() and RANK(), you can generate a list of unique random decimal numbers. The RANK() function ensures that each number is assigned a distinct ranking, which helps eliminate duplicates when the list is sorted.

## Generating a Range of Random Integers Without Duplicates

What if you want to **generate random integers within a specific range, ensuring there are no duplicates**? You can adapt the RAND() and RANK() method to achieve this by using the RANDBETWEEN() function instead of RAND(). Here’s how:

- Set up headers in cells A1 and B1 as described in the previous section.
- In cell A2, enter the following formula to generate random integers between 1 and 100: =RANDBETWEEN(1,100) You can adjust the range by modifying the arguments of the RANDBETWEEN() function. For example, to generate random integers between 50 and 200, you would use =RANDBETWEEN(50,200).
- Copy the formula down to as many cells as needed, depending on the number of random integers you want to generate.
- In cell B2, use the RANK() formula as described earlier: =RANK(A2,$A$2:$A$101) This formula assigns a unique ranking to each random integer based on its position when sorted ascendingly.
- Copy the formula in B2 down to the corresponding cells in column B, matching the number of rows in column A.
- Convert the formulas in column B to values by selecting the cells, copying them, and pasting as values.
- Sort column B in ascending order to obtain a
**list of unique random integers**.

This table shows an example of the results:

Random Integer | Unique Ranking |
---|---|

32 | 12 |

94 | 89 |

67 | 53 |

3 | 1 |

81 | 71 |

… | … |

By using RANDBETWEEN() instead of RAND(), you can generate random integers within a specific range. The RANK() function continues to ensure uniqueness by assigning distinct rankings to each number.

## Generating Unique Random Numbers with RANDARRAY()

For Microsoft 365 subscribers, Excel offers a more straightforward way to **generate random numbers without duplicates** using a single function: RANDARRAY().

To use it:

- In cell A1, enter: =RANDARRAY(100,1,1,100,TRUE) This formula generates an array of 100 unique random integers between 1 and 100. The arguments of the RANDARRAY() function specify the number of rows (100), number of columns (1), minimum value (1), maximum value (100), and whether to exclude duplicates (TRUE).
- Press Ctrl+Shift+Enter to confirm the formula as an array formula. This is necessary because RANDARRAY() returns an array of values rather than a single value.

The RANDARRAY() function eliminates the need for the RANK() workaround, as it has a built-in option to exclude duplicates. However, it is only available in Excel for Microsoft 365, so if you are using an earlier version of Excel, you’ll need to rely on the RAND() and RANK() method.

## Troubleshooting Common Issues

If you encounter issues when trying to **generate random numbers without duplicates in Excel**, double-check the following:

- Make sure your RAND() and RANK() formulas are entered correctly, with the appropriate cell references. A small mistake in the formula can lead to unexpected results.
- Ensure you have copied the formulas down enough rows to generate the desired number of random values. If you don’t copy the formulas down far enough, you won’t get the full set of unique numbers you need.
- Remember to convert the RANK() formula results to values before sorting. If you forget this step, the rankings will recalculate whenever the worksheet is updated, which can disrupt the uniqueness of the results.
- If using RANDARRAY(), confirm you are running Excel for Microsoft 365 and that you have entered the formula as an array formula. Failing to enter it as an array formula will result in an error.

If you still encounter issues after checking these points, try breaking down the process into smaller steps and verifying the results at each stage. This can help identify where the problem lies and make it easier to find a solution.

## Final Thoughts

Generating random numbers without duplicates in Excel is a common task that can be achieved using formulas like RAND() in combination with RANK(), or for Microsoft 365 users, the RANDARRAY() function. By following the step-by-step methods outlined in this article, you can easily **create a list of unique random numbers in Excel** for various applications like data sampling, generating test data, randomizing lists, and more.

The RAND() and RANK() method is versatile and works in all versions of Excel, allowing you to generate unique random decimal numbers or integers within a specific range. The RANDARRAY() function simplifies the process for Microsoft 365 users by offering a built-in option to exclude duplicates.

## FAQs

### What is the difference between RAND() and RANDBETWEEN() functions in Excel?

RAND() generates a random decimal number between 0 and 1, while RANDBETWEEN(bottom, top) generates a random integer between the specified bottom and top numbers, inclusive.

### Can RAND() or RANDBETWEEN() generate unique random numbers without duplicates?

No, RAND() and RANDBETWEEN() alone do not guarantee the exclusion of duplicates. If you generate a large enough set of random numbers using these functions, you are likely to encounter repeats.

### How can I generate random numbers without duplicates using RAND() and RANK() functions?

To generate random numbers without duplicates, use RAND() to generate random decimal numbers, and then use RANK() to assign unique rankings to each number. After converting the RANK() results to values and sorting them in ascending order, you will have a list of unique random numbers.

### Is there a single function in Excel that can generate random numbers without duplicates?

Yes, for Microsoft 365 subscribers, the RANDARRAY() function can generate random numbers without duplicates in a single step. Use the formula =RANDARRAY(rows, columns, min, max, TRUE) to generate unique random numbers.

### What should I do if I encounter issues while trying to generate random numbers without duplicates in Excel?

If you encounter issues, double-check that your formulas are entered correctly, you have copied them down enough rows, and you have converted RANK() results to values before sorting. If using RANDARRAY(), ensure you are running Excel for Microsoft 365 and have entered the formula as an array formula.

Vaishvi Desai is the founder of Excelsamurai and a passionate Excel enthusiast with years of experience in data analysis and spreadsheet management. With a mission to help others harness the power of Excel, Vaishvi shares her expertise through concise, easy-to-follow tutorials on shortcuts, formulas, Pivot Tables, and VBA.