Authoritative definitions of the International System of Units and SI prefixes.
Dedicated unit pair
Gray to Joules per kilogram
Convert Gy to J/kg instantly, then review the formula, assumptions, and rounding guidance.
Radiation unitsInstant result
Decimals
Formula result = input × 1 ÷ 1. 1 Gy = 1 J/kg
Common examples
One value, several units
Milligray1,000 mGy
Rad100 rad
Joules per kilogram1 J/kg
Conversion table
| Gy | J/kg |
|---|---|
| 1 Gy | 1 J/kg |
| 2 Gy | 2 J/kg |
| 5 Gy | 5 J/kg |
| 10 Gy | 10 J/kg |
| 25 Gy | 25 J/kg |
| 50 Gy | 50 J/kg |
| 100 Gy | 100 J/kg |
Conversion chart
1 Gy1 J/kg
5 Gy5 J/kg
10 Gy10 J/kg
25 Gy25 J/kg
50 Gy50 J/kg
Worked example
1 gray equals 100 rad.
Unit definition
Gray (Gy) One gray equals 1 gray.
Unit history
Gray is represented here using its modern SI definition or an internationally accepted relationship to an SI base unit.
Step by step
1. Parse the value, including fractions.
2. Convert Gy to gray.
3. Convert the base value to J/kg and apply your display precision.
Understand the result before using it
Gray to Joules per kilogram converts a value measured in Gray (Gy) into the equivalent value in Joules per kilogram (J/kg). The numerical value changes because the size and definition of the selected unit changes; the underlying quantity does not.
Calculated result
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.
Formula, assumptions, and example
Formula
result = input × 1 ÷ 1
Assumptions
- Gray and Joules per kilogram represent the same absorbed dose quantity.
- The input is expressed in Gy; the output is expressed in J/kg.
- The unit definitions and conventional relationship shown on this page apply.
Worked example
1 Gy = 1 J/kg. For another value, apply the same relationship and round only to the precision your source measurement supports.
When to use it
Good uses
- Read a Gy measurement in a document that expects J/kg.
- Compare a gray value with a value reported in joules per kilogram.
- Check the Gy-to-J/kg arithmetic before copying the result into another calculation.
Limitations
Common mistakes to avoid
- Absorbed dose, equivalent dose, and activity describe different radiation quantities and are not interchangeable.
- Round the output to a precision justified by the original measurement.
- Verify safety-critical, regulated, laboratory, and contractual conversions against the controlling standard.
Sources and further reading
These references explain the underlying standards or provide authoritative context. Your own contract, institution, clinician, product documentation, local code, or governing standard may be the controlling source.
Guidance on unit names, symbols, conversions, and numerical presentation.
Questions about this calculation
How do I convert Gray to Joules per kilogram?
result = input × 1 ÷ 1 Using the displayed relationship, 1 Gy equals 1 J/kg.
How many Joules per kilogram are in one Gray?
One Gray is 1 Joules per kilogram. The displayed digits may be rounded.
Can I reverse the Gy to J/kg conversion?
Yes. Swap the source and target units in the converter. The reverse relationship converts J/kg back to Gy.
Is the Gray to Joules per kilogram result exact?
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.