Weight-based Levothyroxine Dose Calculator for Hypothyroidism in Adults

This weight-based levothyroxine dose calculator provides an evidence-based tool to estimate initial thyroid hormone replacement needs in adults with primary hypothyroidism and minimal residual thyroid function. The formula uses a standard starting dose of 1.6 mcg/kg/day, with adjustments for special populations such as those with obesity, advanced age, or cardiac disease. The calculator is intended for non-pregnant adults under 65 years without ischemic heart disease and serves as a practical aid to guide starting therapy, recognizing the importance of ongoing monitoring, individualized titration, and clinical judgment in optimizing patient outcomes.