Calculating tax payments based on net profit can be easily done using the Sage Intacct Budgeting and Planning model feature.
First, add a new model to your budget and name it (for example "Tax payment"):
Then, add an assumption for the tax rate. Make sure to set its type to "%":
Now, add a new model line from type "Take from budget", select all income budget lines (usually, the groups "Revenues" and "Other income"), and set it to use P&L data:
Add a second model line from type "Take from budget", select all expense budget lines (usually, the groups "Operating expense", "Cost of revenues", and "Other expense"), and set it to use P&L data.
Now add a third model line, which will calculate the tax payment. The line should be from type "Same amount / formula each month", set to the currency you'd like to use:
In the amount field enter the following formula (open the formula assistant by typing "=" in the amount line):
if(revenue - expenses>0,(revenue - expenses)*tax rate,0)
Finally, add the model line to your budget by selecting the "Add to budget" button:
Select to place it under your "Other income and expenses" group, so it won't be included in any of the budget groups you previously selected for your calculation.