Failure-to-Lodge Penalty & GIC Calculator, Australia

A penalty unit is the standard increment the ATO uses to calculate administrative penalties under the Tax Administration Act 1953. The rate is $364 per unit, effective 1 July 2026, verified 1 September 2026. It is set by section 4AA of the Crimes Act 1914 and indexed every three years, so confirm the current value at ato.gov.au before issuing advice. The calculator above defaults to $364 but is editable so you can model past periods or the next indexation.

FTL applies when an entity fails to lodge an approved form (BAS, IAS, ITR, FBT return, TPAR, AS) by its due date. One penalty unit accrues for each 28-day period (or part thereof) the form is overdue, capped at 5 units. The unit count is then multiplied by the entity-size multiplier: 1× for small entities (<$1m turnover), 2× for medium ($1m to $20m), and 5× for large (>$20m), meaning a large entity 5 months late faces up to 25 penalty units, $9,100 at $364 per unit, effective 1 July 2026, verified 1 September 2026.

Submit a written remission request to the ATO setting out the grounds under PS LA 2011/19. Strong grounds include serious illness or hospitalisation, natural disaster, family bereavement, agent error (with corroboration), or system outages preventing lodgement. Include dates, supporting documents, and a statement that the form has now been lodged. First-time offences with prompt rectification are commonly remitted in full; repeated late lodgements are harder to remit.

General Interest Charge (GIC) applies to unpaid tax liabilities and runs from the original due date. Shortfall Interest Charge (SIC) is a lower rate that applies to tax shortfalls revealed by an amended assessment, it covers the period between the original assessment and the amendment, after which GIC takes over. SIC is roughly GIC minus 3 percentage points. Both compound daily. This calculator estimates GIC; SIC would substitute a lower rate over the relevant window.

Registered tax agents access the Lodgement Program, which extends due dates for clients on their register by 31 October. Typical concessions: individual ITRs to 15 May (or 5 June with payment-on-time), Q1/Q3/Q4 BAS by ~4 weeks, FBT returns to 25 June (electronic), and company/SMSF returns generally to 28 February or 15 May depending on risk profile. Self-lodgers cannot access these dates. See the OneBookPlus Lodgement Deadline Calendar for the full grid.

The Lodgement Program is the ATO's published schedule of concessional due dates for tax agents who lodge electronically and maintain an on-time performance benchmark (currently 85% of forms lodged by the program due date). Agents who drop below the benchmark risk losing concessions, a powerful reason to triage clients early and request remission promptly when slippage occurs. New clients added to the agent register by 31 October generally retain access to the concessional dates.