Rads to centigrays
Type a value in rads to see it in centigrays straight away, or type in the second box to convert back.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Type the value in the rads box.
- Read the result in centigrays as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
cGy = rad × 1
Multiply the value in rads by 1 to get centigrays.
Example
To convert 25 rad to centigrays: 25 × 1 = 25 cGy.
Conversion table
| Rads (rad) | Centigrays (cGy) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 5 | 5 |
| 10 | 10 |
| 20 | 20 |
| 25 | 25 |
| 50 | 50 |
| 100 | 100 |
| 250 | 250 |
| 500 | 500 |
| 1,000 | 1,000 |
About the units
- Rad
- An older unit of absorbed dose equal to 100 erg per gram, exactly 0.01 gray, still seen in US references.
- Centigray
- A centigray is exactly one hundredth of a gray and equals one rad, which is why radiotherapy doses use it.
Limits and caveats
- Results are rounded for display and computed with the browser's floating point precision (about 15 significant digits).
- Both unit factors are exact by their official definitions.
Questions about this tool
How many centigrays are in one rad?
1 rad = 1 cGy exactly.
How do I convert rads to centigrays?
Use cGy = rad × 1. For example, 25 rad = 25 cGy.
How many rads are in one centigray?
1 cGy = 1 rad.
What is the difference between gray and sievert?
The gray measures energy actually absorbed, while the sievert adds a weighting for the type of radiation and its biological effect. For X-rays and gamma rays the weighting is 1, so 1 Gy corresponds to about 1 Sv.
Why do radiotherapy teams use centigrays?
A centigray equals exactly one rad, so the switch from rad to the SI unit kept the familiar numbers.