Radiation Exposure / mR → R
Convert Milliroentgens to Roentgens
Convert photon exposure in air using charge per mass. Convert Milliroentgens (mR) to Roentgens (R). Find the formula, worked examples, unit definitions, and practical guidance below.
Reverse: Roentgens to Milliroentgens →
How to convert milliroentgens to roentgens
Exposure in C/kg describes ionization in air. It is not absorbed dose in tissue or equivalent dose in sieverts. Those relationships require radiation and material information.
Use x for the value in mR, b for the intermediate value in C/kg, and y for the result in R.
R = mR × 2.58e-7 ÷ 0.000258
Worked examples
10 mR ≈ 0.01 R
Step 1: (10 × 2.58e-7) ≈ 0.00000258 C/kg.
Step 2: 0.00000258 ÷ 0.000258 ≈ 0.01 R.20 mR ≈ 0.02 R
Step 1: (20 × 2.58e-7) ≈ 0.00000516 C/kg.
Step 2: 0.00000516 ÷ 0.000258 ≈ 0.02 R.
Results are rounded to 12 significant digits. Converting units does not increase the precision of the original measurement. Very large or small values outside JavaScript’s finite numeric range are rejected.
About Milliroentgens
Milliroentgens (mR) measures radiation exposure under the conventions above. The base value in C/kg is (x × 2.58e-7), where x is the numerical value in mR. Factors shown here are rounded for display; calculations use the stored factor.
About Roentgens
Roentgens (R) measures radiation exposure under the conventions above. The base value in C/kg is (x × 0.000258), where x is the numerical value in R. Factors shown here are rounded for display; calculations use the stored factor.
Definitions and sources
Carry the same physical assumptions into subsequent physics calculations.
Milliroentgens to roentgens reference table
| Milliroentgens (mR) | Roentgens (R) |
|---|---|
| 1 | 0.001 |
| 5 | 0.005 |
| 10 | 0.01 |
| 25 | 0.025 |
| 50 | 0.05 |
| 100 | 0.1 |
| 1000 | 1 |
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