Convert Milligrays to Grays (mGy to Gy)
1 milligray (mGy) = 0.001 grays (Gy). 1 Gy = 1000 mGy. Example: 15 mGy = 15 × 0.001 = 0.015 Gy.
Also searched as milligrays to Gy, milligrays in Gy, milligrays into grays, mGy to Gy, mGy in grays, mGy into gray, milligray to gray, mGy to grays converter and how many grays in a milligray.
1 mGy = 0.001 Gy
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk milligray to gray converter to paste a column from Excel.
How to Convert Milligray to Gray
- 1 mGy = 0.001 Gy
- 1 Gy = 1000 mGy
- Example: convert 15 mGy to Gy: 15 mGy = 15 × 0.001 Gy = 0.015 Gy
Formula
Gy = mGy ÷ 1000
Derivation from SI units:
- 1 mGy = 10⁻³ Gy.
- 1 Gy = 1 J of absorbed energy per kg.
Both units are defined exactly, so the factor is exact. Milligray definition: milligray; Gray definition: gray.
Worked examples
- A reading of 0.5 mGy converts to 0.0005 Gy.
0.5 mGy × 0.001 = 0.0005 Gy - A value of 5 mGy is 0.005 Gy.
5 mGy × 0.001 = 0.005 Gy
Milligray to Gray conversion table
| Milligrays (mGy) | Grays (Gy) |
|---|---|
| 0.001 mGy | 0.000001 Gy |
| 0.01 mGy | 0.00001 Gy |
| 0.1 mGy | 0.0001 Gy |
| 0.5 mGy | 0.0005 Gy |
| 1 mGy | 0.001 Gy |
| 2 mGy | 0.002 Gy |
| 5 mGy | 0.005 Gy |
| 10 mGy | 0.01 Gy |
| 50 mGy | 0.05 Gy |
| 100 mGy | 0.1 Gy |
Where it's used
Milligrays are used for CT dose index (CTDIvol), while grays appear in radiotherapy prescriptions. Both measure absorbed dose of ionising radiation, so the conversion is a fixed factor.
Milligray to other absorbed dose units
| Conversion | 1 mGy equals |
|---|---|
| milligray to gray | 0.001 Gy |
| milligray to rad | 0.1 rad |
| milligray to microgray | 1000 µGy |
| milligray to centigray | 0.1 cGy |
| milligray to kilogray | 0.000001 kGy |
| milligray to millirad | 100 mrad |
Frequently asked questions
How many grays are in 1 milligray?
1 mGy = 0.001 Gy.
How do I convert milligrays to grays?
Multiply the value in mGy by 0.001, or divide it by 1000. For example, 15 mGy × 0.001 = 0.015 Gy.
Is the mGy to Gy conversion exact?
Yes. Both units are defined exactly, and 1 mGy is exactly 0.001 Gy.
Sources
- 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 Milligrays to Grays (mGy to Gy). Retrieved October 25, 2026, from https://scientificconverters.com/absorbed-dose/milligrays-to-grays/
IEEE
Scientific Converters, "Convert Milligrays to Grays (mGy to Gy)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/absorbed-dose/milligrays-to-grays/