This working paper estimates multipliers for spending in clean energy and biodiversity conservation to help inform stimulus measures for a post-COVID-19 sustainable recovery. Using a new international dataset, part of which was especially assembled for this analysis, the IMF finds that every dollar spent on key carbon-neutral or carbon-sink activities—from zero-emission power plants to the protection of wildlife and ecosystems—can generate more than a dollar’s worth of economic activity. The estimated multipliers associated with green spending are about 2 to 7 times larger than those associated with non-eco-friendly expenditure, depending on sectors, technologies and horizons. These findings survive several robustness checks and suggest that ‘building back better’ could be a win-win for economies and the planet.