| Masking element | Description |
| 0 | Digit, required. This element will accept any single digit between 0 and 9. |
| 9 | Digit or space, optional. |
| # | Digit or space, optional. If this position is blank in the mask, it will be rendered as a space in the Text property. Plus (+) and minus (-) signs are allowed. |
| L | Letter, required. Restricts input to the ASCII letters a-z and A-Z. This mask element is equivalent to [a-zA-Z] in regular expressions. |
| ? | Letter, optional. Restricts input to the ASCII letters a-z and A-Z. This mask element is equivalent to [a-zA-Z]? in regular expressions. |
| & | Character, required. If the AsciiOnly property is set to true, this element behaves like the “L” element. |
| C | Character, optional. Any non-control character. If the AsciiOnly property is set to true, this element behaves like the “?” element. |
| A | Alphanumeric, required. If the AsciiOnly property is set to true, the only characters it will accept are the ASCII letters a-z and A-Z. This mask element behaves like the “a” element. |
| a | Alphanumeric, optional. If the AsciiOnly property is set to true, the only characters it will accept are the ASCII letters a-z and A-Z. This mask element behaves like the “A” element. |
| . | Decimal placeholder. The actual display character used will be the decimal symbol appropriate to the format provider, as determined by the control's FormatProvider property. |
| , | Thousands placeholder. The actual display character used will be the thousands placeholder appropriate to the format provider, as determined by the control's FormatProvider property. |
| : | Time separator. The actual display character used will be the time symbol appropriate to the format provider, as determined by the control's FormatProvider property. |
| / | Date separator. The actual display character used will be the date symbol appropriate to the format provider, as determined by the control's FormatProvider property. |
| $ | Currency symbol. The actual character displayed will be the currency symbol appropriate to the format provider, as determined by the control's FormatProvider property. |
| All other characters | Literals. All non-mask elements will appear as themselves within MaskedTextBox. Literals always occupy a static position in the mask at run time, and cannot be moved or deleted by the user. |