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The root zone soil water content at field capacity, θ FC , is often crucial for irrigation scheduling and soil-plant-atmosphere modelling. Although θ FC is traditionally determined using methodologies based on matric head or when water flux at the bottom of the root-zone equal to a prescribed negligible flux, these approaches can be problematic for some soils and applications. In this study, a novel water storage approach was used to estimate θ FC for 11 soil texture classes in southeastern Australia (northwest Victoria) by employing the Soil-Water-Atmosphere-Plant (SWAP) model to simulate gravity drainage from saturation in the active root zone (top 60 cm). Field capacity was specified as the average root zone water content corresponding to a 1% relative change in daily soil water storage. We have also estimated flux-based θ FC when prescribed flux at the bottom of the root-zone was 0.1 cm d-1. Three new empirical equations were developed to estimate storage-based θ FC as a function of SWAP-simulated drainage flux out of the root zone, the n parameter of the van Genuchten function, and the saturated soil hydraulic conductivity, K s , or the soil water content at − 100 cm matric head. We have evaluated these three new equations in addition to nine published equations for estimating θ FC. The three new equations were found to be better predictors of θ FC than most of the nine popular equations reported in the literature when compared to flux-based θ FC values. Based on findings from this study the new equations are considered to be effective for irrigation scheduling and crop/climate modelling on the dryland soils of Victoria. Future studies will assess the applicability of the new equations to other parts of Australia. • A process-oriented storage-based criterion is used to estimate field capacity (FC) in SWAP. • Drainage simulation ends when daily changes in soil water storage reach 1%. • Three empirical equations were developed for predicting FC using θ s , θ r , n and K s. • Our equations outperform nine published empirical equations to predict FC. • Matric head-based equations are not sufficiently accurate for estimating FC. [ABSTRACT FROM AUTHOR]