# Access Excel VBA Check Prime Number using custom Function

This tutorial shows a custom Access Excel VBA Function that can check prime number, the Function returns TRUE or FALSE.

## Access Excel VBA Check Prime Number using custom Function

In this tutorial, I will show a custom Access Excel Function that can check prime number, returning TRUE or FALSE. Prime number is an integer that can only be divided by 1 or itself (without remainder). Below are some examples of prime number.

 1–20 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 21–40 73 79 83 89 97 101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 41–60 179 181 191 193 197 199 211 223 227 229 233 239 241 251 257 263 269 271 277 281 61–80 283 293 307 311 313 317 331 337 347 349 353 359 367 373 379 383 389 397 401 409

http://en.wikipedia.org/wiki/List_of_prime_numbers

## Access Excel VBA Function Code – Check Prime Number

```Public Function wIsPrimeNumber(sinput) As Boolean
If sinput = 1 Then
ElseIf sinput > 2 Then
For i = 2 To sinput - 1
If sinput Mod i = 0 Then
Exit Function
End If
Next i
End If
End Function```

## VBA Function Code Algorithm – Check Prime Number

Below is what I have done in the Function. This code is 100% original and I originally created it for a question posted in Microsoft Community. I did not even google for similar Function, let me know if you see any holes I am not aware of.

– Function wIsPrimeNumber returns TRUE or FALSE

– Function returns TRUE by default, unless it falls into IF criteria

– Divide the user input number by 1,2,3,…until number itself-1 , if no reminder for all the calculations, then it should be a prime number,  no action is needed because default is already TRUE (is prime number)

– Otherwise if any one of those calculations have no remainder, then it is not a prime number, and the Function returns FALSE

## VBA Function Syntax – Check Prime Number

`wIsPrimeNumber (sInput)`

sInput is the number you want to check whether it is a Prime Number