Convert Grays to Centigrays (Gy to cGy)
1 gray (Gy) = 100 centigrays (cGy). 1 cGy = 0.01 Gy. Example: 15 Gy = 15 × 100 = 1500 cGy.
Also searched as grays to cGy, grays in cGy, grays into centigrays, Gy to cGy, Gy in centigrays, Gy into centigray, gray to centigray, Gy to centigrays converter and how many centigrays in a gray.
1 Gy = 100 cGy
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk gray to centigray converter to paste a column from Excel.
How to Convert Gray to Centigray
- 1 Gy = 100 cGy
- 1 cGy = 0.01 Gy
- Example: convert 15 Gy to cGy: 15 Gy = 15 × 100 cGy = 1500 cGy
Formula
cGy = Gy × 100
Derivation from SI units:
- 1 Gy = 1 J of absorbed energy per kg.
- 1 cGy = 0.01 Gy = 1 rad.
Both units are defined exactly, so the factor is exact. Gray definition: gray; Centigray definition: centigray.
Worked examples
- A reading of 0.5 Gy converts to 50 cGy.
0.5 Gy × 100 = 50 cGy - A value of 5 Gy is 500 cGy.
5 Gy × 100 = 500 cGy
Gray to Centigray conversion table
| Grays (Gy) | Centigrays (cGy) |
|---|---|
| 0.001 Gy | 0.1 cGy |
| 0.01 Gy | 1 cGy |
| 0.1 Gy | 10 cGy |
| 0.5 Gy | 50 cGy |
| 1 Gy | 100 cGy |
| 2 Gy | 200 cGy |
| 5 Gy | 500 cGy |
| 10 Gy | 1000 cGy |
| 50 Gy | 5000 cGy |
| 100 Gy | 10000 cGy |
Where it's used
Grays are used for radiotherapy prescriptions, while centigrays appear in radiotherapy plans (e.g. 200 cGy per fraction). Both measure absorbed dose of ionising radiation, so the conversion is a fixed factor.
Gray to other absorbed dose units
| Conversion | 1 Gy equals |
|---|---|
| gray to centigray | 100 cGy |
| gray to milligray | 1000 mGy |
| gray to rad | 100 rad |
| gray to microgray | 1000000 µGy |
| gray to kilogray | 0.001 kGy |
| gray to millirad | 100000 mrad |
Frequently asked questions
How many centigrays are in 1 gray?
1 Gy = 100 cGy.
How do I convert grays to centigrays?
Multiply the value in Gy by 100. For example, 15 Gy × 100 = 1500 cGy.
Is the Gy to cGy conversion exact?
Yes. Both units are defined exactly, and 1 Gy is exactly 100 cGy.
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 Grays to Centigrays (Gy to cGy). Retrieved October 25, 2026, from https://scientificconverters.com/absorbed-dose/grays-to-centigrays/
IEEE
Scientific Converters, "Convert Grays to Centigrays (Gy to cGy)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/absorbed-dose/grays-to-centigrays/