What is an Input Mask?

Malcolm Tatum
Malcolm Tatum

An input mask is an expression that helps to define what type of contact is allowed in a given field on a template. The idea behind the input mask is to keep the data entry process somewhat uniform and minimize the chances for incorrect data to be entered into the field. In some cases, the input field entry can be configured to allow automatic field input as a way of saving time and resources.

Man holding computer
Man holding computer

The creation of an input mask takes place during the computer programming process. Fields on a template are established with specific control values. The values make it impossible to enter data that is not compatible with the values. For example, a field that contains an input mask that only allows letters will automatically reject the input of numbers.

Another common application of an input mask has to do with automatically converting the input into an acceptable format. For example, the mask may require that the date field on the template specifies a format that is structured as date/month/year. Even if the individual entering the date into the field follows a month/date/year format, the input system reads the entered data and automatically converts it into the proper form.

Automatic input is also extremely helpful in many applications. In this scenario, the input mask is structured to trigger an automatic fulfilling of one or more fields, based on data entered in a previous field. For example, when someone enters a first and last name into those fields, the input mask ties this information back to previously processed data and automatically enters that data into one or more succeeding fields. As a result, it is only necessary to update a few fields and save the changes, rather than re-enter every piece of data in order to create the new file or document.

It is also not uncommon for an input mask to place a limit on the number of characters that may be entered into the field, as well as require a minimum number of characters. This can be especially helpful when the file must contain data such as credit card numbers, telephone numbers, and similar information. This safeguard will alert the individual entering the data if there are too many characters entered, or if there are not enough characters entered to meet the minimum number. Doing so helps to minimize errors and prevents the need to correct the file at a later date.

Malcolm Tatum
Malcolm Tatum

After many years in the teleconferencing industry, Michael decided to embrace his passion for trivia, research, and writing by becoming a full-time freelance writer. Since then, he has contributed articles to a variety of print and online publications, including EasyTechJunkie, and his work has also appeared in poetry collections, devotional anthologies, and several newspapers. Malcolm’s other interests include collecting vinyl records, minor league baseball, and cycling.

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Discussion Comments


How can we do masking in ms access? After masking, does the date format change on the basis of system settings? If we can change the settings of our system from US to UK, then what will happen in masking?


@SwiftBeats - A Microsoft Access input mask can also format passwords. You can define what kind of characters you want to appear whenever a user enters information. The default character is the asterisk, but you can use whatever character that you want.


@SwiftBeats - An Access input mask can also limit the formatting of the input as well as the number of characters that it contains. For example, you can enforce dashes for social security numbers or parentheses for the area codes of a phone number. The Microsoft Access wizard will display the list of available templates for use.


When using an input mask in Access, are there limitations on what you can actually enter to control how certain data is entered? I know you can limit the number of characters, but what other uses can be used to limit what users put in the input text?

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