An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »


What is the relationship between exposure rate and dose rate?

Exposure rate is the amount of ionizing radiation per hour in a person’s vicinity (measured in milliRoentgen per hour, mR/h), whereas dose rate is the biological effect on the body from exposure to that radiation (measured in nanoSieverts per hour, nSv/h). As an approximation, a radiological dose rate of 1 mR/h is roughly equal to an exposure rate of 10,000 nSv/h.

For more information about typical exposures and dose rates, visit About Exposure and Dose Rates or Learn About RadNet.

Return to Frequent Questions About RadNet.