In this paper, new formulae are presented to estimate the wave overtopping rate of mass-armoured berm breakwaters. In addition to the effects of dimensionless crest freeboard and crest width, the formulae consider the influences of water depth at the toe of the structure and structure slope on the overtopping rate through simple dimensionless parameters. The performances of the new formulae were then compared with those of the existing empirical prediction formulae. Statistical indicators such as Root Mean Square Error (RMSE) showed that the new formulae are better predictors than the existing ones.