The present paper proposes a new and simple mechanical model for predicting the maximum sloshing wave height (MSWH) in a partially filled, laterally excited cylindrical tank. The proposed model is a linear, two degree of freedom spring-mass-damper system which consists of two masses representing the sloshing and non-sloshing mass of the partially filled cylindrical tank. The model is validated through a series of experiments conducted on a cylindrical tank filled with water which is mounted in a slosh test rig. The proposed model successfully captures the beating phenomenon observed in sloshing wave height, when the tank is laterally excited near the resonant frequency of the liquid. The present study leads to a simpler, accurate and faster mechanical model which can predict the MSWH, frequency of sloshing liquid and the lateral sloshing force. The model can be readily used by the design engineers, instead of time consuming numerical models like computational fluid dynamics and smoothed particle hydrodynamics, in the preliminary design phase of any structure involving lateral sloshing and provide quick results which will substantially lead to shorter design cycle time. © 2019 Elsevier Ltd