Radiation Dose Calculator
Gray to sievert, with the radiation weighting factor.
Work out Radiation Dose. Gray to sievert, with the radiation weighting factor. Says where the model stops being reliable.
Energy deposited per kilogram. 1 Gy is 1 joule per kilogram.
A unit conversion, not a safety assessment. Exposure decisions belong with a qualified radiation protection professional.
Equivalent dose
1 mSv
Comparable to routine diagnostic imaging
Gray measures energy deposited — one joule per kilogram — and says nothing about biological effect. Sievert applies a weighting factor for how the energy is deposited: alpha particles dump theirs over a very short track and do about twenty times the damage of the same energy from X-rays. For scale, natural background is roughly 2–3 mSv a year depending on where you live, a chest X-ray is about 0.1 mSv, and a CT scan runs from 2 to 10 mSv. This is a unit conversion with the standard ICRP weighting factors applied. It is not a safety assessment or a clinical judgement, and nothing here should be used to decide about an exposure — that is a question for a radiation protection officer or a physician.
How the Radiation Dose Calculator works
Convert absorbed dose in grays to equivalent dose in sieverts using the ICRP radiation weighting factors. Gray measures energy deposited; sievert accounts for how much biological damage that energy does, which differs twentyfold between X-rays and alpha particles.
Also known as: gray to sievert converter · millisievert calculator · absorbed dose vs equivalent dose · radiation weighting factor calculator
Frequently asked questions
What is the difference between a gray and a sievert?
A gray is one joule of energy absorbed per kilogram, and says nothing about biological effect. A sievert applies a weighting factor for how the energy is deposited — the same gray from alpha particles does about twenty times the damage of one from X-rays.
What are the radiation weighting factors?
1 for X-rays, gamma rays and beta particles, 2 for protons, and 20 for alpha particles and heavy ions. Neutrons vary from 2.5 to 20 depending on energy.
How much radiation is background?
Roughly 2 to 3 mSv a year, varying substantially with altitude, local geology and radon levels. A chest X-ray is about 0.1 mSv and a CT scan runs from 2 to 10.
Can this tell me whether an exposure was safe?
No. This is a unit conversion with standard weighting factors applied. Assessing an actual exposure is a matter for a radiation protection officer or a physician, and nothing here should be used to make that judgement.
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