Input Tax and Output Tax calculating wrong figures

Question

Hi,
I have created Input Tax and Output Tax codes in SAP.
Input Tax- 3%
Output Tax- 4%
All the configuration is done as required. But when I am posting the Purchase and Sales Invoice, the tax amount is not calculating correctly.
For example:
Input Tax Calculation should be:
Vendor A/C.............. Cr 30000-
Expense A/C............ Dr 29100
Input Tax A/C............ Dr 900 (@3% on 30000)
Input Tax Calculation in SAP:
Vendor A/C.............. Cr 30000-
Expense A/C............ Dr 29126.21
Input Tax A/C............ Dr 873.79 (@3% on 30000)
The same is happening to Output Tax transactions.
Please advice.

Answer 1

My understanding about the Input Tax and Output Tax was wrong. In the issue reported
Input Tax Calculation should be:
Vendor A/C.............. Cr 30000-
Expense A/C............ Dr 29100
Input Tax A/C............ Dr 900 (@3% on 30000)---my understanding was wrong.
Input Tax 3% should be charged on Expense amount, in this case Rs 30000. But because in the editing option calculate tax on net amount option was not selected, hence SAP was giving the below entry, which is correct as well.
Vendor A/C.............. Cr 30000-
Expense A/C............ Dr 29126.21
Input Tax A/C............ Dr 873.79 (@3% on 29126.21) which is correct.
Hence, the Vendor amount should be Expense + Input Tax= 30000 * 3%=900 + 30000 (expense) = 30900.
Correct Entry should be:
Vendor A/C...............Cr 30900
Expense A/C............Dr 30000
Input Tax A/C............Dr 900
Resolved. Pankaj has given the correct answer.