Megasievert is 1000000 sievert units.
Megasieverts to Millisieverts Converter — MSv to mSv
Convert Megasievert (MSv) to Millisievert (mSv) using the exact conversion factor (1 megasievert = 1,000,000,000 millisievert). See the formula, worked examples, and conversion table.
Megasieverts to Millisieverts 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.
Millisievert is 0.001 sievert units.
Result = input x 1e+6 / 0.001.
Equivalent Dose units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Megasieverts to Millisieverts
Megasievert and Millisievert 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: Megasievert is 1000000 sievert units, and millisievert is 0.001 sievert units.
Formula
millisieverts = megasieverts × 1000000000
This factor comes from each unit's defined relationship to the category's base unit: 1 megasievert equals 1000000 base units, and 1 millisievert equals 0.001 base units, so dividing one by the other gives the direct megasievert-to-millisievert factor of 1000000000.
Simple example
1 MSv × 1000000000 = 1,000,000,000 mSv
1 megasievert = 1,000,000,000 millisieverts.
Real-world example
10 MSv × 1000000000 = 10,000,000,000 mSv
10 megasieverts = 10,000,000,000 millisieverts.
Conversion table
| Megasievert (MSv) | Millisievert (mSv) |
|---|---|
| 0.001 MSv | 1,000,000 mSv |
| 0.01 MSv | 10,000,000 mSv |
| 0.1 MSv | 100,000,000 mSv |
| 1 MSv | 1,000,000,000 mSv |
| 10 MSv | 10,000,000,000 mSv |
| 100 MSv | 100,000,000,000 mSv |
Reverse conversion: Millisievert to Megasievert
1 mSv × 1e-9 = 1e-9 MSv
1 millisievert = 1e-9 megasieverts.
megasieverts = millisieverts × 1e-9
For a page dedicated to this direction, see Millisievert to Megasievert.
Understanding the Megasievert (MSv)
Megasievert is 1000000 sievert units.
Understanding the Millisievert (mSv)
Millisievert is 0.001 sievert units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many millisieverts are in 1 megasievert?
1 megasievert equals 1,000,000,000 millisieverts, using the exact defined conversion factor rather than an estimate.
How do I convert megasievert to millisievert?
Multiply the megasievert value by 1000000000. The converter above does this instantly to whatever precision you set.
How do I convert millisievert back to megasievert?
Use the reverse factor: 1 millisievert equals 1e-9 megasieverts. You can also use the swap control in the converter above to flip the direction instantly.
What is a megasievert?
Megasievert (MSv) is a unit of radiation.
What is a millisievert?
Millisievert (mSv) is a unit of radiation.
Is the megasievert to millisievert conversion exact?
Yes. Both megasievert and millisievert are defined by fixed standards rather than physical artifacts, so the factor of 1000000000 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.