Red guava is a species that has been relatively little studied; despite this, it is widely distributed throughout Brazil. To understand the domestication of the species, it is essential to understand the leaf area of red guava. In this regard, this study aimed to estimate the leaf area of red guava through image analysis software. Red guava leaves were collected from the Fruit Orchard, and characteristics such as length, width, leaf mass, and leaf area were evaluated. The latter was estimated after the leaves were digitized and processed using ImageJ software. Additionally, the mass of leaf disks, detached from the basal portion of the leaves, was evaluated. A completely randomized design was employed. Data were analyzed descriptively and correlated using Pearson's correlation. Red guava leaves showed significant variability in mass, linear measurements, and leaf area. Leaf area estimation through image analysis software is cost-effective, easily executable, and an efficient methodology for evaluating this characteristic.