Zeptogray is 1e-21 gray units.
Zeptograys to Milligrays Converter — zGy to mGy
Convert Zeptogray (zGy) to Milligray (mGy) using the exact conversion factor (1 zeptogray = 1e-18 milligray). See the formula, worked examples, and conversion table.
Zeptograys to Milligrays converter
Converter
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.
Milligray is 0.001 gray units.
Result = input x 1e-21 / 0.001.
Absorbed Dose units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Zeptograys to Milligrays
Zeptogray and Milligray both belong to the radiation-measurement family, though radiation quantities fall into genuinely distinct categories: absorbed dose (gray, rad) measures energy deposited in matter, equivalent dose (sievert, rem) weights that for biological harm, and activity (becquerel, curie) measures how often a radioactive source decays — this page only converts between units of the same kind. Specifically: Zeptogray is 1e-21 gray units, and milligray is 0.001 gray units.
Formula
milligrays = zeptograys × 1e-18
This factor comes from each unit's defined relationship to the category's base unit: 1 zeptogray equals 1e-21 base units, and 1 milligray equals 0.001 base units, so dividing one by the other gives the direct zeptogray-to-milligray factor of 1e-18.
Simple example
1 zGy × 1e-18 = 1e-18 mGy
1 zeptogray = 1e-18 milligrays.
Real-world example
10 zGy × 1e-18 = 1e-17 mGy
10 zeptograys = 1e-17 milligrays.
Conversion table
| Zeptogray (zGy) | Milligray (mGy) |
|---|---|
| 0.001 zGy | 1e-21 mGy |
| 0.01 zGy | 1e-20 mGy |
| 0.1 zGy | 1e-19 mGy |
| 1 zGy | 1e-18 mGy |
| 10 zGy | 1e-17 mGy |
| 100 zGy | 1e-16 mGy |
Reverse conversion: Milligray to Zeptogray
1e-18 mGy × 1e+18 = 1 zGy
1e-18 milligrays = 1 zeptograys.
zeptograys = milligrays × 1e+18
For a page dedicated to this direction, see Milligray to Zeptogray.
Understanding the Zeptogray (zGy)
Zeptogray is 1e-21 gray units.
Understanding the Milligray (mGy)
Milligray is 0.001 gray units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many milligrays are in 1 zeptogray?
1 zeptogray equals 1e-18 milligrays, using the exact defined conversion factor rather than an estimate.
How do I convert zeptogray to milligray?
Multiply the zeptogray value by 1e-18. The converter above does this instantly to whatever precision you set.
How do I convert milligray back to zeptogray?
Use the reverse factor: 1 milligray equals 1e+18 zeptograys. You can also use the swap control in the converter above to flip the direction instantly.
What is a zeptogray?
Zeptogray (zGy) is a unit of radiation.
What is a milligray?
Milligray (mGy) is a unit of radiation.
Is the zeptogray to milligray conversion exact?
Yes. Both zeptogray and milligray are defined by fixed standards rather than physical artifacts, so the factor of 1e-18 used above is exact to as many digits as you choose to display.
What's the difference between absorbed dose, equivalent dose, and activity?
Absorbed dose (gray, rad) measures the energy radiation deposits in matter. Equivalent dose (sievert, rem) adjusts that figure for how harmful different types of radiation are to biological tissue. Activity (becquerel, curie) measures how often a radioactive source decays, independent of how much dose a person actually receives from it.