Tax calculation incorrect

OK great so this how Manager behaves when adding line items… as in the red box, thank you for clearly pointing it out.

The test as to tax amount is this

If you invoice 10 items on “individual” invoices - their tax adds up to xx.xx
Therefore if you invoice the 10 items on a “single” invoice - the Tax should still be xx.xx
If you use the Invoice total then the Tax could calculate to xx.xy

@compuit I find it easier to work with tax inclusive numbers that way rounding errors change the distribution between tax and not tax but not the line item total value. Doing it that way decreases reconciliation errors.

This idea would probably also help

Hi all, have been having the same problem with multiple invoices having a difference on the third decimal of 1 digit up/down.

Following this discussion, i did try 4 different ways to try matching the supplier invoice ( 1,111.572) but could not get to match, see below.


1st TRIAL - STANDARD WAY (unit price + discount + TAX)

2nd TRIAL - (unit price with TAX inclusive + discount)

3rd TRIAL - (unit price discounted + TAX)

4rd TRIAL - (unit price discounted with tax inclusive)

I guess the solution is the same as what i have been doing for the past invoices with the same problem, enter all items without TAX, and add a line entry using the GL account “Tax Payable” under Liabilities with the total TAX value, in this case 52.932.

Is this a good workaround? or there is a better solution to make it work???

Thank you.

You are never going to get Manager to match this particular invoice, because either:

  • Your supplier’s arithmetic is incorrect, or
  • The supplier’s presentation method does not match the calculation method.

The total of VAT amounts for individual line items on the supplier’s invoice should be 52.933, exactly as Manager calculates it with any of your methods. The total amount of the invoice should be 1111.573, again exactly as Manager calculates.

The invoice makes it look like VAT was calculated on each line and summed. But your supplier appears to have actually calculated VAT on the total tax-exclusive amount, which yields 52.932. Most automated accounting systems calculate tax on individual line items and add those amounts. This is necessary because individual line items might later be returned or adjusted. Or they might be subject to different tax rates. The method your supplier appears to have used is what most old-fashioned, manual calculation systems used. The rounding difference between the two methods is only one fil.

Check your local tax regulations. You will discover either method is acceptable. Over time, such small differences are likely to average out, with some suppliers doing things one way and one the other, and with some differences adding to and some subtracting from your tax liability account. Your tax authority will be aware of the two methods.

If you really want to make the invoice match, you will have to create a 100% custom tax code and add a line item to the purchase invoice for the 1 fil adjustment.

Reduce the unit price on one of the line items until the amount matches the suppliers invoice

Hi @tut instead of your solution:

What could be the implications of doing this way:

See results of this way below:



Thank you.

@AJD i tried, could not match both (tax and total invoice value) at the same time.


  • You would give up the ability to track taxable transactions.
  • You would compromise your ability to enter debit notes if you return a single line item to a supplier.
  • Various built-in tax reports will not work correctly.
  • You will seriously confuse any auditor or inspector who examines your records.
  • You would lose the ability to enter tax-inclusive purchase invoices, which some of your suppliers might furnish.
  • While this will not impact purchase invoices, if you took the same approach on sales invoices, you would be breaking your jurisdiction’s tax laws, which require line by line indication of tax codes applied. But your purchase invoices will not match your suppliers’ tax invoices (sales invoices), making it very difficult to resolve any future disputes.

Overall, not a good practice.

Is your tax authority going to be concerned about a extremely small difference?

If they are then you need to do as Tut suggested.

.Or you could make the tax match the suppliers invoice and then use a rounding account in your P&L to make the invoice total match by adding another line in the invoice. This will avoid having to create a new tax code.