Radiation Dose Converter
Convert absorbed dose in grays and rads, or equivalent dose in sieverts and rems: two different quantities, kept apart.
Written by Rahman · Last reviewed
Quick answer
Absorbed dose is energy deposited per unit mass. The SI unit is the gray, one joule per kilogram, and one rad is 0.01 Gy. Sieverts and rems also appear here: they share the same dimensions but measure equivalent dose: absorbed dose weighted for the biological effect of the radiation type. They convert one to one only because that weighting factor is 1 for X-ray, gamma and beta radiation.
Energy deposited per kilogram of matter, regardless of radiation type. This is the physical quantity a dosimeter measures.
| Gray (Gy) | 1 |
| Milligray (mGy) | 1000 |
| Microgray (µGy) | 1000000 |
| Rad (rad) | 100 |
| Millirad (mrad) | 100000 |
| Joule per kilogram (J/kg) | 1 |
About the Radiation Dose Converter
Absorbed dose measures the amount of radiation energy deposited per unit of mass. The SI unit is the gray; the older rad is also supported, along with dose-equivalent units.
It is fundamental to radiation protection and medical treatment.
Frequently Asked Questions
What is absorbed dose?
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Absorbed dose is the energy of ionising radiation deposited per kilogram of material, measured in gray.
How many rad are in a gray?
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One gray equals 100 rad.
What is the difference between gray and sievert?
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The gray measures physical energy absorbed, while the sievert measures the biological effect, accounting for the type of radiation.