Working with Credit Card Numbers

Credit Card numbers are 16-digit numbers and if you ever enter a 15 digit number into a cell, you may discovered that Excel changes the last digit to a zero.

So why would Excel change this number? It comes down to how Excel was coded. Excel can handle only 15 digits of numerical accuracy.

So what do you do if you need to enter a 16 digit number manually? Well first ask yourself if Excel is secure enough to store valuable credit card information. If you still want to proceed, you have 3 easy ways of entering in the information...

  1. Precede the credit card number with an apostrophe. Excel then interprets the data as a text string rather than as a number.
  2. Pre-format the cell or range by using the Text number format. Select the range, choose Home > Number and then select Text from the Number Format drop-down control.
  3. Enter the card number with dashes or spaces. Embedding a non-numeric character such as a dash forces Excel to interpret the entry as text.


Excel 2013 - Understanding the Protected View

You may have already encountered an Excel feature known as Protected View.

So what is Protected View. Weill its all about protecting you from malware.

Now you are saying to yourself... Hold on, I don't own any mid evil armor. What is all the fuss about malware and why should I care?

In a simplified definition, Malware refers to something that can harm your computer. There are many ways that hackers can manipulate Excel files so that harmful code can execute. The Protected View essentially prevents these types of attacks by opening a file in a protected environment. This is often called a sandbox by developers.

When you open an Excel workbook that you downloaded from the web, you’ll see a warning message above the Formula bar.  In addition, Excel’s title bar displays the message.

If you’re certain that the file is safe you can click Enable Editing.

If you don’t enable editing, you’ll be able to view the contents of the workbook, but you won’t be able to make any changes to it.

What causes Protected View?

Protected View kicks in for the following:

  1. Files downloaded from the Internet
  2. File attachments opened from Outlook
  3. Files opened from potentially unsafe locations, such as your Temporary Internet Files Folder
  4. Files that are blocked by File Block Policy 
  5. Files that have expired digital signatures
So be sure to know where that file comes from and when in doubt, don't enable editing.