The Date Range represents the time period during which a Tax Formula is effective.
The tax rate defined by the Formula is effective from the Start Date, through the End Date, including all dates in between.
If the Formula should always be effective, leave both the Start Date and End Date blank (Null). This has the same effect as entering the Date Range of / / to / / which represents January 1, 1985 through an indefinite date in the future.
Tax Formulas may be set up ahead of time, become effective only when the Start Date is reached, and become ineffective when the End Date is reached.
Warning: If the Start Date is in the past, the Tax Formula applies to transactions already saved and is effective when they are edited. It is recommended to avoid using past Starting Dates when entering new Tax Formulas.
Note: Tax Formulas should never just be changed (see warning above). When tax rates change a new Tax Formula should be created for the new tax rate with a Start Date that represents the first day the new tax rate is effective. The old Tax Formula's End Date should be edited to reflect that last day the old tax rate was effective.
See:
When Tax Rates Change - How to Change Tax Rates
Tax Tables - General Information
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