Authoritative definitions of the International System of Units and SI prefixes.
Unit conversion
mSv to Sv Converter (Millisieverts to Sieverts)
1 mSv = 0.001 Sv. Enter a value to convert mSv to Sv, then use the formula and table below. Displayed digits may be rounded.
Radiation unitsInstant result
Decimals
Formula result = input × 0.001 ÷ 1. 1 mSv = 0.001 Sv
Nonzero results too small for the selected decimal places use scientific notation.
Nonzero results too small for the selected decimal places use scientific notation.
Common examples
One value, several units
Sieverts0.001 Sv
Microsieverts1,000 µSv
Rem0.1 rem
Conversion table
| mSv | Sv |
|---|---|
| 1 mSv | 0.001 Sv |
| 2 mSv | 0.002 Sv |
| 5 mSv | 0.005 Sv |
| 10 mSv | 0.01 Sv |
| 25 mSv | 0.025 Sv |
| 50 mSv | 0.05 Sv |
| 100 mSv | 0.1 Sv |
Conversion chart
1 mSv0.001 Sv
5 mSv0.005 Sv
10 mSv0.01 Sv
25 mSv0.025 Sv
50 mSv0.05 Sv
Worked example
1 mSv = 0.001 Sv. Apply the selected conversion formula to other input values.
Unit definition
Millisieverts (mSv) One millisieverts equals 0.001 sievert.
Unit history
Millisieverts 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 mSv to sievert.
3. Convert the base value to Sv and apply your display precision.
Important
Equivalent dose already includes the applicable radiation weighting factor.
Understand the result before using it
Millisieverts (mSv) and sieverts (Sv) use the same unit with different prefixes. Milli means one thousandth, so 1 mSv = 0.001 Sv. Divide a value in mSv by 1,000 to express it in Sv.
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 ÷ 1000
Assumptions
- Millisieverts and Sieverts represent the same equivalent dose quantity.
- The input is expressed in mSv; the output is expressed in Sv.
- Equivalent dose already includes the applicable radiation weighting factor.
Worked example
For 5 mSv, divide 5 by 1,000 to get 0.005 Sv. For 0.2 mSv, divide 0.2 by 1,000 to get 0.0002 Sv. These calculations change only the unit prefix.
When to use it
Good uses
- Express a recorded mSv value in Sv when a table or calculation uses sieverts.
- Check prefix arithmetic when comparing values reported in mSv and Sv.
Limitations
Common mistakes to avoid
- This page performs unit arithmetic only; it does not interpret what a reported value means.
- Preserve the measured quantity: a value in mSv/h includes a time denominator and is not a value in mSv.
- Changing mSv to Sv does not convert the quantity into gray or becquerel.
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 mSv to Sv?
Divide by 1,000. For example, 1 mSv equals 0.001 Sv.
What is 5 mSv in Sv?
5 mSv ÷ 1,000 = 0.005 Sv. The value is expressed in a different unit prefix.
How many millisieverts are in one sievert?
One sievert equals 1,000 millisieverts. To convert Sv back to mSv, multiply by 1,000.