Convert Grays to Rads
Convert Grays (Gy) to Rads (rad) instantly and accurately.
Conversion Formula
rad = Gy × 100
About Grays
The gray (Gy) is the SI coherent unit of absorbed radiation dose, defined as 1 joule of energy deposited per kilogram of matter. Named after Harold Gray (British radiobiologist, 1905-1965). Used globally in radiotherapy: curative tumour doses 40-80 Gy fractionated; total body irradiation before bone marrow transplant 12-14 Gy. 1 Gy = 1 J/kg = 100 rad.
About Rads
The rad (rad) equals exactly 0.01 Gy = 100 erg/g. The pre-SI unit of absorbed dose, defined by the ICRU in 1953, still widely used in the US in radiation therapy (cGy = rad numerically), radiation biology, and NRC regulations. Whole-body 50% lethal dose (LD50) for humans ~350-450 rad. 1 rad = 0.01 Gy = 1 cGy.
Quick Reference Table
| Grays (Gy) | Rads (rad) |
|---|---|
| 1 Gy | 100 rad |
| 2 Gy | 200 rad |
| 5 Gy | 500 rad |
| 10 Gy | 1000 rad |
| 25 Gy | 2500 rad |
| 50 Gy | 5000 rad |
| 100 Gy | 10000 rad |