The global extinction crisis is intensifying rapidly, driven by habitat loss, overexploitation, climate change, invasive species, and disease. This unprecedented loss of species not only threatens ecological integrity but also undermines ecosystem services vital for human survival. In response, many countries have set ambitious conservation targets such as halting species extinctions, yet the necessary financial commitments to achieve this are rarely prescribed. Estimating costs can be achieved using an ensemble of spatially variable species-specific cost models for threat abatement activities. We employ this method to provide a cost assessment to halt extinctions for Australia's priority terrestrial and freshwater species. We show that it will cost ~AUD15.6 billion/year for 30 y to halt extinctions for these 99 priority species (comparable to 1% of Australia's GDP). The more ambitious objectives to move priority species down one threat category (~AUD103.7 billion/year) or remove from the threatened species list entirely (~AUD157.7 billion/year) would require considerably more investment. Regardless of what is spent, we found that 16 (16%) priority species could not be removed from the threatened species list due to extensive historical declines and pervasive, ongoing, unmanageable threats, such as climate change. But implementing these efforts could ensure conservation benefits for over 43% of all nationally listed nonmarine threatened species. Adequate funding is crucial for meeting government commitments and requires both government leadership and private sector investment.