Absorbed dose (gray) measures energy deposited per kilogram of tissue. Equivalent dose (sievert) multiplies it by a weighting factor because alpha particles and neutrons do more biological damage than X-rays for the same energy. For X-rays, gamma rays and beta particles the factor is 1, so 1 Gy gives 1 Sv.
How to use the Radiation Dose Converter
- Absorbed dose
- Type of radiation
- Every result field is editable: type into Absorbed dose or any other result and Absorbed dose plus every other field update to match.
Results update as you type, and every field accepts the units shown in its menu.
How it works
Your dose is converted to grays, then multiplied by the ICRP radiation weighting factor to give the equivalent dose in sieverts and its sub-units.
Typical doses for comparison
| Exposure | Approximate dose |
|---|---|
| Dental X-ray | 0.005 mSv |
| Long-haul flight (10 h) | 0.03–0.05 mSv |
| Chest X-ray | 0.02–0.1 mSv |
| Mammogram | 0.4 mSv |
| Head CT scan | 2 mSv |
| Annual natural background (world average) | 2.4 mSv |
| Annual limit for radiation workers (ICRP) | 20 mSv averaged over 5 years |
Good to know
Effective dose (also in sieverts) adds tissue weighting factors on top of the radiation weighting factor to estimate whole-body risk. This converter handles units and radiation type only; it is not a substitute for a medical physicist’s dose assessment.
Inputs explained
| Field | What to enter |
|---|---|
| Absorbed dose | Units: mGy, Gy, µGy, rad, krad |
| Type of radiation | Choose one: X-rays, gamma rays, beta (w_R = 1), Protons (w_R = 2), Neutrons, typical (w_R ≈ 10), Alpha particles, heavy ions (w_R = 20) |
What each result means
- Equivalent dose = [Absorbed dose] × [Type of radiation]
- In rem = [Absorbed dose] × [Type of radiation]
- In microsieverts = [Absorbed dose] × [Type of radiation]
Formula
H (Sv) = D (Gy) × w_R1 rad = 0.01 Gy; 1 rem = 0.01 SvWorked example
Inputs — Absorbed dose: 1 mGy; Type of radiation: X-rays, gamma rays, beta (w_R = 1).
Results — Absorbed dose = 0.001 Gy; In rad = 0.1 rad; Equivalent dose = 1 mSv; In rem = 0.1 rem; In microsieverts = 1,000 µSv.
Key terms
- Gray (Gy)
- SI unit of absorbed dose: 1 joule of radiation energy per kilogram.
- Sievert (Sv)
- SI unit of equivalent and effective dose, adjusting for radiation type and tissue.
Frequently asked questions
How much radiation is a chest X-ray?
About 0.02–0.1 mSv effective dose.
What is the average yearly background dose?
About 2.4 mSv worldwide (around 3 mSv in the U.S.).
Is a sievert the same as a gray?
Only when the weighting factor is 1 (X-rays, gamma, beta).
What formula does the Radiation Dose Converter use?
H (Sv) = D (Gy) × w_R.