Long sequences of digits (e.g. numerals such as phone, serial and credit card numbers) can be difficult for users to read, remember and compare.
A simple and proven way to increase their readability is to split up the digits into visually separated groups:
Do
5471 3250 0192 1718
Credit card number with digits grouped
Don't
5471325001921718
Credit card number without digits grouped
The symbols for separating the digit groups vary based on tradition and cultural context. Make sure to follow the (local) conventions.
Do
+1 (800) 322 8316
Telephone number with digits grouped
Don't
18003228316
Telephone number without digits grouped