Radiation Exposure Converter

Convert radiation exposure between röntgen (R), milliroentgen (mR), and coulombs per kilogram (C/kg). Exposure measures ionization of air by X-rays and gamma rays.

Common Radiation Exposure Conversions

FromTo
1 R2.58×10⁻⁴ C/kg
1 C/kg3,876 R
1 mR0.001 R
Background radiation (annual)~0.3 R = 3 mSv
Chest X-ray~0.01 mSv

Radiation Exposure Unit Definitions

Röntgen (R)
Historical unit of X-ray and gamma exposure.
Coulomb/kg (C/kg)
SI unit of radiation exposure.
Milliroentgen (mR)
0.001 R.

Frequently Asked Questions

What is a safe level of radiation exposure?

Natural background radiation averages ~3 mSv/year (300 mR). Medical guidelines limit occupational exposure to 50 mSv/year.

What is the difference between röntgen and sievert?

Röntgen (R) measures ionization in air from X/gamma rays. Sievert (Sv) measures biological effect on tissue. 1 R ≈ 0.0096 Gy ≈ 0.0096 Sv for X-rays.

How much radiation does a chest X-ray give?

A chest X-ray delivers approximately 0.1 mSv — about the same as 10 days of natural background radiation.