Roentgens to Milliroentgens Converter
Enter the radiation exposure in roentgens below to convert it to milliroentgens.
Convert Roentgens to Milliroentgens
Enter a value in roentgens (R) to convert to milliroentgens (mR).
Roentgen to Milliroentgen Conversion Table
Table showing various roentgen measurements converted to milliroentgens. Click any preset value or arrow to load it into the converter.
How to Convert Roentgens to Milliroentgens
To convert roentgens to milliroentgens, multiply the radiation exposure by the following conversion ratio: 1,000 milliroentgens/roentgen.
Since one roentgen is equal to 1,000 milliroentgens, you can use this simple formula to convert:
The radiation exposure in milliroentgens is equal to the radiation exposure in roentgens multiplied by 1,000.
For example, here's how to convert 5 roentgens to milliroentgens using the formula above.
How Many Milliroentgens Are in a Roentgen?
There are 1,000 milliroentgens in a roentgen, which is why we use this value in the formula above.
Our roentgen to milliroentgen calculator automatically converts your radiation exposure measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Roentgens and milliroentgens are both units used to measure radiation exposure. Keep reading to learn more about each unit.
What Is a Roentgen?
A roentgen is a unit of radiation exposure equal to 0.000258 coulombs per kilogram (C/kg), the base unit for radiation exposure. Legacy X-ray/gamma exposure unit defined as exactly 2.58×10⁻⁴ C/kg. [1]
The roentgen is classified as a standard unit of radiation exposure. Roentgens can be abbreviated as R; for example, 1 roentgen can be written as 1 R.
When working with roentgens (R) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.
In practice, roentgens (R) are widely used across fine-tolerance laboratory, analytical, and micro-scale radiation exposure measurements within international standard workflows, engineering documentation, and technical data sheets.
What Is a Milliroentgen?
A milliroentgen is a unit of radiation exposure equal to 0.000000258 coulombs per kilogram (C/kg), the base unit for radiation exposure. One-thousandth of a Roentgen (2.58×10⁻⁷ C/kg). [2]
The milliroentgen is classified as a standard unit of radiation exposure. Milliroentgens can be abbreviated as mR; for example, 1 milliroentgen can be written as 1 mR.
In the metric system, "milli" is the standard SI prefix for thousandths, or 10⁻³. This makes the milliroentgen (mR) a convenient decimal multiple of the coulomb per kilogram (C/kg).
In practice, milliroentgens (mR) are widely used across fine-tolerance laboratory, analytical, and micro-scale radiation exposure measurements within international standard workflows, engineering documentation, and technical data sheets.
When converting radiation exposure between roentgens (R) and milliroentgens (mR), keep full floating-point precision (1 R = 1,000 mR; 1 mR = 0.001 R) during intermediate calculations and round only the final milliroentgen figure to match your instrument tolerance.
More Roentgen & Milliroentgen Conversions
Need to calculate in the opposite direction? Use our milliroentgens to roentgens calculator to switch your starting unit immediately. You can also explore related tools such as converting milliroentgens to roentgens, converting roentgens to coulombs per kilogram, or converting coulombs per kilogram to millicoulombs per kilogram.
Frequently Asked Questions
References
- [1]NIST OWM StandardNIST OWM (SI Units — Length)·Radiation-Exposure Metrology Standard — Roentgens (R) to Milliroentgens (mR)
- [2]BIPM SpecificationBIPM (SI Base Unit: Metre (m))·Unit Specifications: Roentgen (R) & Milliroentgen (mR)
- [3]NIST HB 133 ReferenceNIST HB 133 (NIST Handbook 133 (2019 Ed.))·Conversion Factors & Mathematical Basis (R to mR)