# Gravitational waves from first-order phase transitions: Towards a better prediction

Over the next few decades, we will have an exciting opportunity to test gravitational waves (GWs) from the early Universe with space interferometries. In this talk, we focus on GWs from first-order phase transitions and present recent efforts to improve the prediction on the GW spectrum. We first present an efficient numerical scheme to calculate GWs from sound waves (under the assumption that the system is in the linear regime) based on 2010.00971 (with T.Konstandin and H.Rubira).