Microsoft Access provides two field properties that produce similar results: the Format property and the InputMask property.
Use the Format property to display data in a consistent format. For example, if you set the Format property for a Date/Time field to Medium Date format, all dates entered will display in this form: 12-Jan-1999. If a user of your database enters a date as 01/12/99 (or any other valid date format), Microsoft Access will convert the display to the Medium Date format when the record is saved.
The Format property affects only how a value is displayed, not how it is stored in the table. Also, a display format isn't applied until the data entered is saved
If you define both a display format and an input mask for a field, Microsoft Access uses the input mask when you are adding or editing data, and the Format setting determines how the data is displayed when the record is saved. When using both Format and InputMask properties, be careful that their results don't conflict.
International data display formats
Microsoft Access can display a wide range of international formats. To help ensure consistency among applications, Microsoft Access uses the regional settings in Microsoft Windows Control Panel for the predefined Number and Date/Time formats. If your data isn't displayed in the right format for your country/region, change the regional settings specified in Control Panel.
Changes made to the formats of regional settings in Windows Control Panel will be automatically reflected in your database for Currency fields if the Format property setting is blank. However, this only affects the format; no conversion of currency values will be made. Therefore, transferring data between computers with different regional settings can result in incorrect currency data.
For example, when using the Currency format on a field where the Format property setting is blank, a value of 5,47 kr on a computer set for Denmark converts to $5.47 on a computer set for the United States. To prevent such errors, define a custom format for the currency, such as #,## kr. The custom format overrides the regional settings specified in Windows Control Panel. Similar problems won't occur when transferring standard number, date, or time data between computers with different regional settings.