What can I check to determine why tax is not being calculated on invoices?
There are three important factors that determine the tax calculated on an invoice.
1. The account should be marked taxable.
Tax rate always comes from the account level and are applied to taxable Items on the invoice only.
2. Items on the invoice should be taxable
Example: Work Types, Service, Retainers, Products, etc.
3. If the tax was enabled before or after generating the invoice.
Once an invoice is generated, if any item which is a part of this invoice is not taxable tax will not be calculated for it.
The items that are marked taxable will follow the tax rate of the Account associated with the invoice.
If the setting was modified after generating the invoice, the invoice will have to be voided and the billing has to be re-done for the tax settings to be applied.