Radiation Converter
Free radiation converter: convert between gray (Gy), sievert (Sv), rad, millisievert (mSv), rem, and more. Absorbed and equivalent dose units for scientists and medical professionals.
About This Calculator
The Radiation Converter lets you convert between all common radiation units for both absorbed dose and equivalent/effective dose. Select the dose type, enter a value, choose source and target units, and get instant accurate results. This tool is essential for medical physicists, radiologists, nuclear engineers, radiation safety officers, students, and anyone working with ionizing radiation measurements.
For absorbed dose, the converter supports gray (Gy), milligray (mGy), centigray (cGy), microgray (µGy), and rad. Absorbed dose measures the energy deposited in any material by ionizing radiation. For equivalent dose, it supports sievert (Sv), millisievert (mSv), microsievert (µSv), rem, and millirem (mrem). Equivalent dose accounts for the biological effectiveness of different radiation types by applying a radiation weighting factor (WR) to the absorbed dose. For X-rays, gamma rays, and beta particles, the weighting factor is 1, meaning 1 Gy = 1 Sv. For alpha particles, WR = 20, so 1 Gy = 20 Sv.
The converter includes an interactive chart showing your value converted to every unit in the selected dose category for easy comparison. All conversions use standard factors: 1 Gy = 100 rad, 1 Sv = 100 rem, 1 mSv = 0.1 rem.
Regional Notes
India: The Atomic Energy Regulatory Board (AERB) sets occupational dose limits at 20 mSv/year averaged over 5 years, following ICRP recommendations. Medical radiation safety is regulated under the Atomic Energy (Radiation Protection) Rules, 2004.
US: The Nuclear Regulatory Commission (NRC) sets the occupational dose limit at 50 mSv (5 rem) per year, with a lifetime limit of 10 mSv × age. The public dose limit is 1 mSv (0.1 rem) per year.
UK: The Health and Safety Executive (HSE) enforces the Ionising Radiations Regulations 2017, with occupational limits of 20 mSv/year and public limits of 1 mSv/year, following EU Basic Safety Standards.
Frequently Asked Questions
What is the difference between gray and sievert?
Gray (Gy) measures absorbed dose — the energy deposited in any material by ionizing radiation. Sievert (Sv) measures equivalent or effective dose, which accounts for the biological effect of different radiation types on human tissue. For X-rays and gamma rays, 1 Gy equals 1 Sv, but for alpha particles, 1 Gy equals 20 Sv due to higher biological damage.
How do I convert mSv to rem?
To convert millisievert (mSv) to rem, multiply by 0.1. For example, 1 mSv equals 0.1 rem. Alternatively, 1 rem equals 10 mSv. The conversion is straightforward since both measure equivalent dose with the ratio 1 Sv = 100 rem.
What is the typical radiation dose from a chest X-ray?
A standard chest X-ray delivers approximately 0.1 mSv (0.01 rem) of effective dose. This is equivalent to the background radiation exposure received over about 10 days. Dental X-rays deliver about 0.005 mSv, while a CT scan of the abdomen delivers around 8 mSv.
What are the common radiation dose limits for occupational exposure?
The annual occupational dose limit is 20 mSv per year averaged over 5 years (with no single year exceeding 50 mSv) in most countries following ICRP recommendations. In the US, the NRC sets the limit at 50 mSv per year. The public dose limit is 1 mSv per year. Pregnant workers have a limit of 1 mSv for the remainder of the pregnancy.
How do you convert rad to gray?
To convert rad to gray, divide by 100. One gray equals 100 rad. For example, 50 rad equals 0.5 Gy. Both measure absorbed dose — the gray is the SI unit while the rad is the CGS unit.
What is a banana equivalent dose (BED)?
A banana equivalent dose (BED) is an informal unit of radiation exposure, approximately 0.1 microsievert (0.0001 mSv). Bananas contain potassium-40, a naturally occurring radioactive isotope. Eating one banana exposes you to about 0.1 µSv of radiation, which is negligible compared to natural background radiation of about 2.4 mSv per year.
What is the annual background radiation exposure worldwide?
The average annual background radiation exposure is about 2.4 mSv per person worldwide, varying from 1-10 mSv depending on location. This comes from natural sources: radon gas (about 1.3 mSv), cosmic radiation (0.4 mSv), terrestrial radiation (0.5 mSv), and internal radiation from food (0.3 mSv).
Is this radiation converter free to use?
Yes, this radiation converter is completely free to use with no registration or limits. Convert between gray, sievert, rad, rem, and all common radiation units instantly.