Convert Roentgen to Milligray
Enter the number of roentgens that you want to convert to milligrays.
How to Convert Roentgens to Milligrays
The roentgen and milligray are both units of radiation dose. 1 roentgen equals 8.77 milligrays. This means to convert roentgens to milligrays, you multiply by 8.77.
Formula
Step-by-Step Example
Convert 5 R to milligrays:
We need to convert roentgens to milligrays
Since 1 R = 8.77 mGy, multiply by 8.77
5 × 8.77 = 43.85
5 R = 43.85 mGy
Roentgen to Milligray Conversion Table
Quick reference table for common roentgen to milligray conversions. Click any value for detailed calculation.
| Roentgens (R) | Milligrays (mGy) |
|---|---|
| 1 R | 8.77 mGy |
| 2 R | 17.54 mGy |
| 5 R | 43.85 mGy |
| 10 R | 87.7 mGy |
| 15 R | 131.55 mGy |
| 20 R | 175.4 mGy |
| 25 R | 219.25 mGy |
| 50 R | 438.5 mGy |
| 100 R | 877 mGy |
About These Units
Roentgen (R)
The roentgen (R) measures ionization produced by X-rays or gamma rays in air. One roentgen produces 2.58×10⁻⁴ C/kg of ionization. Approximately: 1 R ≈ 8.77 mGy or 0.877 rad in soft tissue. Named after Wilhelm Röntgen, discoverer of X-rays.
Milligray (mGy)
A milligray (mGy) equals 0.001 gray or 0.1 rad. Common medical imaging doses: CT scan 10-30 mGy, mammogram 2-3 mGy, fluoroscopy 20-50 mGy. Diagnostic reference levels often specified in mGy.
Frequently Asked Questions
How do I convert roentgens to milligrays?
To convert roentgens to milligrays, multiply the value by 8.77. For example, 10 R = 87.7 mGy.
How many milligrays are in 1 roentgen?
1 roentgen equals 8.77 milligrays.
What is the formula for roentgens to milligrays?
The formula is: mGy = R × 8.77.