GST amounts that are automatically calculated in General, Sales, and Purchase can be manually adjusted in Microsoft Dynamics 365 NAV Business Central.  A manual GST adjustment maybe required, in cases such as, an invoice received from a vendor does not match to the GST amount calculated in MS Dynamics NAV.

The GST Difference can be activated in Journals, Sales, and Purchase transactions, and an amount threshold for the difference can be set. Let’s see how it’s done.

Step 1:

The amount threshold can be set in the Max. GST Difference Allowed field in the General Ledger Setup.  Navigate to ‘Departments > Financial Management > Setup Administration > General Ledger Setup’. Alternatively, search for ‘General Ledger Setup’ in the search box.  For this example we will set the Max. GST Difference Allowed as 5.

General Ledger setup for GST difference allowed

Step 2:

To enable the GST Difference, open Purchase & Payable Setup and put a check mark in the Allow GST Difference field.

Allowing the GST difference to be set in MS NAV

The Allow GST Difference field can also be found in the Sales & Receive Setup and General Journal Batches to enable the functionality in Sales and Journals respectively.


Now that all the setups have been configured, users can now enter a transaction and manually change the GST amount.  To do this create a Purchase Invoice and click the Statistics button to manually modify the GST Amount.  In the screenshot below, the GST Amount has been modified to 98.

Modifying the GST amount in MS NAV 365

Note: NAV will display an error if the GST Amount that has been set is more than the maximum GST Difference Allowed.

Defining settings of a GST difference alerts the user to a discrepancy


In this instance a Purchase Invoice has been posted. To see the GST Entries that have been recorded navigate to account and view the related GST Entries.

View the GST entries to see the GST amount for the line item.

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