In spite of its strong starting position, the sustainability of public finances in an ageing Germany is at risk. FiFo Policy Fellow and one of the "Five Sages" Martin Werding, with Benjamin Läpple and Sebastian Schirner, conducted the calculations for the Federal MoF's 6th Sustainability Report. If policies remain unchanged, German public debt will more than double to 140% of GDP by 2070 in the best-case scenario and rise to a dizzying 345% in the worst-case scenario. FiFo Report 33 provides the calculations and possible solutions in the full version.