Grays to rads
Type a value in grays to see it in rads 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 grays box.
- Read the result in rads as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
rad = Gy × 100
Multiply the value in grays by 100 to get rads.
Example
To convert 25 Gy to rads: 25 × 100 = 2,500 rad.
Conversion table
| Grays (Gy) | Rads (rad) |
|---|---|
| 1 | 100 |
| 2 | 200 |
| 3 | 300 |
| 5 | 500 |
| 10 | 1,000 |
| 20 | 2,000 |
| 25 | 2,500 |
| 50 | 5,000 |
| 100 | 10,000 |
| 250 | 25,000 |
| 500 | 50,000 |
| 1,000 | 100,000 |
About the units
- Gray
- The SI unit of absorbed dose, equal to one joule of radiation energy absorbed per kilogram of matter.
- Rad
- An older unit of absorbed dose equal to 100 erg per gram, exactly 0.01 gray, still seen in US references.
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 rads are in one gray?
1 Gy = 100 rad exactly.
How do I convert grays to rads?
Use rad = Gy × 100. For example, 25 Gy = 2,500 rad.
How many grays are in one rad?
1 rad = 0.01 Gy.
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.