How is GST calculated in Abtrac compared to Xero
Xero GST calculation
Xero invoice lines are rounded to the nearest cent before tax is calculated.
Xero calculates the GST for each individual line on a transaction, with each GST amount rounded to the nearest cent.
The total GST on the invoice is the sum of the individual line item amounts. The line by line calculation of GST is a standard GST calculation process that enables different GST rates to be used in the same invoice.
Abtrac GST calculation
Abtrac allows invoice lines exclusive of tax to be unrounded, e.g. 30% of $450.99 = $135.297.
Abtrac also calculates the GST for each individual line on a transaction, but does not round each GST amount to the nearest cent.
The total GST on the invoice is the sum of the individual line item amounts which is then rounded.
This total GST value is then cross checked against the total invoice amount exclusive of GST. The Abtrac GST calculation process still enables different GST rates to be used in the same invoice, but also ensures that GST on the total invoice amount is correct mathematically.
When do Abtrac line amounts have more than 2 decimals.
Where Abtrac has allowed an invoice line with more than 2dp you’ll also see this warning message on the invoice line.
Sometimes this occurs for automatically generated invoices where timesheet rounding isn’t set to mathematical.
Sometimes it happens when your disbursment lines include more than two decimals.
You can also set an invoice line to deliberately be more than two decimals when you require the tax inclusive invoice amount to be a round number.
Why is my Xero invoice total due different to my Abtrac invoice total?
Sometimes if an invoice has multiple lines, the total GST can vary by a few cents when compared with an amount that is calculated on the total taxable amount of the invoice.
Comparison of Abtrac vs Xero invoice line numbers
| Abtrac | Xero | Both | Abtrac | Xero | Abtrac | Xero | |
| Invoice Line Amount | Rounded Invoice Line Amount | Tax Rate to Apply | Invoice Line Tax Amount | Rounded Invoice Line Tax Amount | Total Invoice Line Amount incl Tax | Rounded Total Invoice Line Amount incl Tax | |
| 211.25 | 211.25 | 0.1 | 21.125 | 21.13 | |||
| 200.00 | 200.00 | 0.0 | 0.00 | 0.00 | |||
| 555.75 | 555.75 | 0.1 | 55.575 | 55.58 | |||
| 100.6667 | 100.67 | 0.1 | 10.067 | 10.07 | |||
| Invoice total ex GST (2dp) | 1067.67 | 1067.67 | |||||
| GST total on invoice (2dp) | 86.77 | 86.78 | |||||
| Invoice total incl GST (2dp) | 1154.44 | 1154.45 |
How to find any invoice total differences between the two systems
In Abtrac each batch uploaded to Xero includes a summary of totals in the View Invoice batch screen. Go to Accounting > Invoices > View Invoice batch to review totals for the most recent upload.
When uploading invoices to Xero from Abtrac you can optionally set a Xero invoice delivery status of “Draft”. You can then review the total of all draft invoices, make any rounding adjustments if required, and then set the invoice status to Approved.
Alternately, if you are using Abtrac to send both invoices and statements you can adjust for any rounding issues after payments have been reconciled by following the steps below.
See also:
Sending Statements from Abtrac
Removing links to invoices on Xero Statements
How to adjust for GST discrepancies in Xero
You can adjust for the small GST variance Xero by making a rounding adjustment.
To adjust the total invoice amount in Practice Manager, add a cost to the invoice with the following details:
- Quantity – either positive or negative 1 (one)
- Unit Cost – 0 (zero)
- Unit Price – the amount of the adjustment, eg 0.01
- Tax Rate – None
Alternatively, you could adjust the invoiced amount for some tasks and costs so that some line items round up and others round down until the accumulated rounding difference is eliminated.
Abtrac KB#2201