GST and Stamp Duty Split Calculator

Australian business insurance premiums carry GST of 10% and, in every state and the Northern Territory, insurance stamp duty set by the state. Duty is generally calculated on the premium including GST (and, in NSW, including the emergency services levy on property-type cover), so the two taxes compound. The ACT abolished insurance duty, so ACT policies generally carry GST only.

How it works. If the base premium is B, GST is 10% and duty is d, the total is B x 1.1 x (1 + d). The tax share of the total is 1 - 1 / (1.1 x (1 + d)). Enter your total and the share for your state; the tool shows the tax and the base premium.

Shares to enter (based on general insurance duty rates published by state revenue offices; confirm the current rate for your class of cover): duty 9% (NSW, Queensland) = 16.597%; duty 10% (Western Australia, Tasmania, Northern Territory, and Victorian non-business cover) = 17.355%; duty 11% (South Australia) = 18.100%; Victorian business insurance renewed 1 July 2026 to 30 June 2027 at 7% = 15.038%; no duty (ACT, or NSW small business exempt liability cover) = 9.091%.

Worked example (illustrative, NSW liability policy for a business with turnover of $2 million or more). Base premium $1,200. GST = $120, so $1,320. Duty = 9% x $1,320 = $118.80. Total = $1,438.80. Check: $1,438.80 x 16.597% = $238.80 of tax, leaving $1,200.

Limits. Broker fees attract GST and are treated differently from the premium; property cover in NSW includes the emergency services levy; some classes (for example workers compensation, NSW professional indemnity at 5%, and some health or life products) have different duty treatment; NSW small businesses with turnover under $2 million are exempt from duty on public, product and professional liability cover, and Victoria is phasing out duty on business insurance by 1 July 2033. A GST-registered business can usually claim the GST as an input tax credit, but not the stamp duty. Check the tax invoice for the exact figures.