Authoritative definitions of the International System of Units and SI prefixes.
Dedicated unit pair
Milligray to Gray
Convert mGy to Gy instantly, then review the formula, assumptions, and rounding guidance.
Radiation unitsInstant result
Decimals
Formula result = input × 0.001 ÷ 1. 1 mGy = 0.001 Gy
Common examples
One value, several units
Gray0.001 Gy
Rad0.1 rad
Joules per kilogram0.001 J/kg
Conversion table
| mGy | Gy |
|---|---|
| 1 mGy | 0.001 Gy |
| 2 mGy | 0.002 Gy |
| 5 mGy | 0.005 Gy |
| 10 mGy | 0.01 Gy |
| 25 mGy | 0.025 Gy |
| 50 mGy | 0.05 Gy |
| 100 mGy | 0.1 Gy |
Conversion chart
1 mGy0.001 Gy
5 mGy0.005 Gy
10 mGy0.01 Gy
25 mGy0.025 Gy
50 mGy0.05 Gy
Worked example
1 gray equals 100 rad.
Unit definition
Milligray (mGy) One milligray equals 0.001 gray.
Unit history
Milligray 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 mGy to gray.
3. Convert the base value to Gy and apply your display precision.
Understand the result before using it
Milligray to Gray converts a value measured in Milligray (mGy) into the equivalent value in Gray (Gy). 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 × 0.001 ÷ 1
Assumptions
- Milligray and Gray represent the same absorbed dose quantity.
- The input is expressed in mGy; the output is expressed in Gy.
- The unit definitions and conventional relationship shown on this page apply.
Worked example
1 mGy = 0.001 Gy. 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 mGy measurement in a document that expects Gy.
- Compare a milligray value with a value reported in gray.
- Check the mGy-to-Gy 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 Milligray to Gray?
result = input × 0.001 ÷ 1 Using the displayed relationship, 1 mGy equals 0.001 Gy.
How many Gray are in one Milligray?
One Milligray is 0.001 Gray. The displayed digits may be rounded.
Can I reverse the mGy to Gy conversion?
Yes. Swap the source and target units in the converter. The reverse relationship converts Gy back to mGy.
Is the Milligray to Gray 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.