Convert Millirads to Grays (mrad to Gy)
1 millirad (mrad) = 0.00001 grays (Gy). 1 Gy = 100000 mrad. Example: 15 mrad = 15 × 0.00001 = 0.00015 Gy.
Also searched as millirads to Gy, millirads in Gy, millirads into grays, mrad to Gy, mrad in grays, mrad into gray, millirad to gray, mrad to grays converter and how many grays in a millirad.
1 mrad = 0.00001 Gy
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk millirad to gray converter to paste a column from Excel.
How to Convert Millirad to Gray
- 1 mrad = 0.00001 Gy
- 1 Gy = 100000 mrad
- Example: convert 15 mrad to Gy: 15 mrad = 15 × 0.00001 Gy = 0.00015 Gy
Formula
Gy = mrad ÷ 100000
Derivation from SI units:
- 1 mrad = 10⁻⁵ Gy = 10 µGy.
- 1 Gy = 1 J of absorbed energy per kg.
Both units are defined exactly, so the factor is exact. Millirad definition: millirad; Gray definition: gray.
Worked examples
- A reading of 0.5 mrad converts to 0.000005 Gy.
0.5 mrad × 0.00001 = 0.000005 Gy - A value of 5 mrad is 0.00005 Gy.
5 mrad × 0.00001 = 0.00005 Gy
Millirad to Gray conversion table
| Millirads (mrad) | Grays (Gy) |
|---|---|
| 0.001 mrad | 1 × 10⁻⁸ Gy |
| 0.01 mrad | 1 × 10⁻⁷ Gy |
| 0.1 mrad | 0.000001 Gy |
| 0.5 mrad | 0.000005 Gy |
| 1 mrad | 0.00001 Gy |
| 2 mrad | 0.00002 Gy |
| 5 mrad | 0.00005 Gy |
| 10 mrad | 0.0001 Gy |
| 50 mrad | 0.0005 Gy |
| 100 mrad | 0.001 Gy |
Where it's used
Millirads are used for older X-ray dose figures, while grays appear in radiotherapy prescriptions. Both measure absorbed dose of ionising radiation, so the conversion is a fixed factor.
Millirad to other absorbed dose units
| Conversion | 1 mrad equals |
|---|---|
| millirad to gray | 0.00001 Gy |
| millirad to milligray | 0.01 mGy |
| millirad to rad | 0.001 rad |
| millirad to microgray | 10 µGy |
| millirad to centigray | 0.001 cGy |
| millirad to kilogray | 1 × 10⁻⁸ kGy |
Frequently asked questions
How many grays are in 1 millirad?
1 mrad = 0.00001 Gy.
How do I convert millirads to grays?
Multiply the value in mrad by 0.00001, or divide it by 100000. For example, 15 mrad × 0.00001 = 0.00015 Gy.
Is the mrad to Gy conversion exact?
Yes. Both units are defined exactly, and 1 mrad is exactly 0.00001 Gy.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "rad (absorbed dose)".
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4 (becquerel, gray, sievert, lux) and Table 2 (candela).
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Millirads to Grays (mrad to Gy). Retrieved October 25, 2026, from https://scientificconverters.com/absorbed-dose/millirads-to-grays/
IEEE
Scientific Converters, "Convert Millirads to Grays (mrad to Gy)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/absorbed-dose/millirads-to-grays/