Gray is absorbed dose in joules per kilogram.
Gray to Rem
Convert Gray (Gy) to Rem (rem) instantly. Free online radiation converter with formulas, tables and examples.
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Radiation Converter
Convert radioactivity, absorbed dose, and equivalent dose units by compatible radiation family.
Context values
Some unit families need one extra value for a physically accurate result.
Rem is 0.01 sievert.
rem = Gy × 100
Results update instantly for Gray to Rem conversions.
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Formula
1 Gray = 100 Rem
rem = Gy × 100
Gy = rem ÷ 100
Conversion table
| 1 Gy | 100 rem |
| 2 Gy | 200 rem |
| 5 Gy | 500 rem |
| 10 Gy | 1000 rem |
| 20 Gy | 2000 rem |
| 50 Gy | 5000 rem |
| 100 Gy | 10000 rem |
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Frequently asked questions
How many Rems are in one Gray?
One Gray equals 100 Rems.
How do I convert Gray to Rem?
Multiply the number of Grays by 100 to get Rems. To go the other way, multiply Rems by 0.01 (or divide by 100) to get Grays.
Is this conversion exact?
Yes. This conversion uses the exact defined relationship between Gray and Rem, so the result shown is mathematically precise (rounded only for display).
When is Gray to Rem conversion commonly used?
It is commonly used in nuclear medicine, radiation safety, health physics, and scientific research involving radioactivity and radiation dose.
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About this conversion
Gray and Rem are units used in the radiation family of measurements. Gray measures absorbed radiation dose (energy deposited per unit mass), while Rem measures equivalent radiation dose (biological risk-weighted dose). This page provides the direct numeric ratio between the two units. This converter uses the precise relationship 1 Gray = 100 Rems (equivalently 1 Rem = 0.01 Grays), so results stay accurate for nuclear medicine, radiation safety, health physics, and scientific research.