Definitive Pro’s T-Shirt Size Estimating feature empowers resource managers to develop early-stage cost estimates for projects, even when data is sparse. By allowing resource managers to define t-shirt sizes (extra small, small, medium, large, extra-large) based on customized guidelines, this tool provides a simplified yet effective method for preliminary project assessment. Managers can quickly align a project’s scope with a corresponding t-shirt size, facilitating an initial resource allocation and cost estimation. This feature enables high-level planning and timeline creation, ensuring that projects are realistically scoped and resourced from the outset. The t-shirt size estimating feature enhances forecasting accuracy, supports agile project management practices, and helps organizations make informed decisions early in the project lifecycle, ultimately leading to more efficient and effective resource utilization.