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...
- Precede the credit card number with an apostrophe. Excel then interprets the data as a text string rather than as a number.
- 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.
- 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.