Rad to Gray Converter

About this calculator

Rad and gray (Gy) both measure absorbed radiation dose — the energy deposited by ionizing radiation per unit mass of tissue or material — but on different scales: the gray is the modern SI unit, defined as 1 joule per kilogram, while the rad is the older CGS unit still seen in some legacy US medical and industry records. The relationship is fixed: 1 Gy = 100 rad.

Radiologists, medical physicists and radiation safety officers use this conversion when comparing dose figures from older equipment or historical patient records (in rad) against modern reporting standards and international literature (in gray), ensuring dose limits and treatment plans stay consistent regardless of which unit a given source used.