Precise total body surface area estimation is paramount for effective burn care. This study aimed to validate the E-Burn app, a digital tool, by comparing its total body surface area estimations against the established Lund and Browder chart, the clinical gold standard. A prospective, cross-sectional study was conducted on 101 burn cases. Total body surface area was independently estimated in parallel using both the E-Burn app and the Lund and Browder chart. Data were analysed using Wilcoxon signed rank tests, Intraclass Correlation Coefficients, and Bland-Altman plots to assess systematic difference, absolute agreement, and bias. The E-Burn app demonstrated excellent agreement with the Lund and Browder chart, achieving an outstanding Intraclass Correlation Coefficients of 0.997. Although a statistically significant median difference was identified (p < 0.001), Bland-Altman analysis quantified this as a clinically minor mean bias of -0.35%. Crucially, the 95% limits of agreement were impressively narrow (+1.32% to -2.02%), indicating minimal random variation and high consistency. The E-Burn app is a precise and highly reliable tool for TBSA estimation, with its minor bias being clinically inconsequential. While this single-centre study warrants future multi-centre validation, these findings robustly support the app’s integration into clinical practice to enhance efficiency and consistency, critically supporting the development of future innovative digital burn tools in Malaysia.