When a tax system withholds tax in advance, keep the estimated tax separate from the amount paid ahead. They are two different steps of the settlement.
An example with numbers
Say your calculated annual tax is $4,800 and $4,300 was withheld. Under these simplified assumptions, $500 would be due. With $5,100 paid in advance, there would be $300 overpaid. These are teaching figures that apply no country's rules.
Try it with your numbers
Write down the jurisdiction and tax year before comparing tax and advance payments. Check what each amount includes in your official documents.
This calculator is on its way. In the meantime, you can do the calculation on paper or in a spreadsheet.
Example figures for learning purposes. They are not a recommendation and do not replace professional advice.