Sievert (Sv)
The SI unit of equivalent and effective radiation dose.
Category: SI equivalent/effective dose
One unit equals: 1 Sv
Conversion result
100 rem
1 Sv × 100 = 100 rem
Conversion factor
100
Scientific notation
1.000000E+02
Relationship
1 Sv = 100 rem
Convert radiation dose units
Enter one non-negative value, select source and destination units, then control how the result is displayed. Instant browser calculation and PHP server validation use the same conversion factors.
Batch conversion
Paste up to 1,000 values separated by new lines, semicolons, or commas. The source and destination units above are applied to every row.
Instant batch results
| Line | Input | Output | Status |
|---|
Calculation history
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Quick conversion table
The table uses the currently selected source and destination units. Change either selector to update it instantly.
| Sievert (Sv) | Rem (rem) |
|---|---|
| 0.000001 | 0.0001 |
| 0.00001 | 0.001 |
| 0.0001 | 0.01 |
| 0.001 | 0.1 |
| 0.01 | 1 |
| 0.1 | 10 |
| 1 | 100 |
| 10 | 1,000 |
| 100 | 10,000 |
Formula used
rem = sieverts × 100
sieverts = rem ÷ 100
Therefore, 1 Sv = 100 rem and 1 rem = 0.01 Sv.
General conversion method
Every supported unit is first converted to sieverts. The sievert value is then divided by the target unit’s sievert factor.
Output = Input × Source factor ÷ Target factor
Worked example
Convert 0.025 Sv to rem:
0.025 × 100 = 2.5 rem
The conversion factor is exact for these units.
How to use this calculator
- Enter a non-negative radiation dose. Decimal and scientific notation are accepted.
- Select the unit of the entered value, such as sievert, millisievert, rem, or millirem.
- Select the unit required for the result. Use the swap button to reverse both units instantly.
- Choose precision, notation, separators, and trailing-zero preferences.
- Read the result, equation, factor, scientific notation, and one-unit relationship above the form.
- Copy, print, share, batch-convert, or export the result when needed.
Supported radiation dose units
Millisievert (mSv)
One thousandth of a sievert.
Category: SI equivalent/effective dose
One unit equals: 0.001 Sv
Microsievert (µSv)
One millionth of a sievert.
Category: SI equivalent/effective dose
One unit equals: 0.000001 Sv
Nanosievert (nSv)
One billionth of a sievert.
Category: SI equivalent/effective dose
One unit equals: 1.000000000000E-9 Sv
Rem (rem)
A traditional unit of equivalent and effective radiation dose.
Category: Traditional equivalent/effective dose
One unit equals: 0.01 Sv
Millirem (mrem)
One thousandth of a rem.
Category: Traditional equivalent/effective dose
One unit equals: 0.00001 Sv
Microrem (µrem)
One millionth of a rem.
Category: Traditional equivalent/effective dose
One unit equals: 1.000000000000E-8 Sv
Understanding sieverts and rem
What the units describe
The sievert and rem are used for equivalent or effective radiation dose. These quantities are designed to express biological relevance after radiation weighting and, for effective dose, tissue weighting are considered. A sievert belongs to the International System of Units, while rem is a traditional unit still encountered in some reports, regulations, training materials, and instruments.
Why the conversion is straightforward
The relationship between sievert and rem is fixed: one sievert equals one hundred rem. This means direct conversion requires only multiplication or division by one hundred. Prefixes change the scale but not the underlying relationship. For example, one millisievert equals one hundred millirem, while one microsievert equals one tenth of a millirem.
Choosing a readable unit
Radiation values often span many orders of magnitude. A small environmental reading may be easier to read in microsieverts, while a larger value may be clearer in millisieverts or sieverts. Traditional displays may use millirem instead of rem for ordinary monitoring values. The calculator keeps the selected target unit, but its optional readable-unit suggestion can point to a more convenient scale.
Precision and significant figures
The mathematical conversion factor is exact, yet a reported measurement may not be exact. Displaying many decimal places does not improve the accuracy of the original instrument or source. Match the result’s significant figures to the quality of the input data. Scientific notation is especially useful for tiny values, and engineering notation keeps exponents in multiples of three.
Use the right dose quantity
A numeric value without its quantity and unit can be misleading. Confirm whether a source reports absorbed dose, equivalent dose, effective dose, dose rate, committed dose, or another radiation quantity. This converter is intended for equivalent and effective dose units expressed in sievert-family or rem-family units. A dose rate also needs a time basis, such as per hour.
Practical use cases
The converter can support classroom calculations, instrument display checks, regulatory document review, occupational radiation protection, laboratory record preparation, and communication between SI-based and traditional unit systems. It provides arithmetic and formatting assistance only. Decisions about exposure, treatment, emergency response, workplace controls, or regulatory compliance require qualified professional interpretation.
Important distinction: sievert is not gray
Do not apply a universal gray-to-sievert conversion.
Gray and rad measure absorbed dose. Sievert and rem describe equivalent or effective dose.
Absorbed dose
Gray (Gy) and rad describe energy deposited per unit mass. They do not, by themselves, apply radiation weighting or tissue weighting.
Equivalent dose
Equivalent dose can be calculated from absorbed dose using a radiation weighting factor: H = D × wR.
A separate absorbed-to-equivalent dose calculator should request the radiation type or a validated weighting factor. Effective dose may require additional tissue weighting and cannot be inferred from a dose value alone.
Reference relationships
| Relationship | Equivalent value |
|---|---|
| 1 sievert | 100 rem |
| 1 rem | 0.01 sievert |
| 1 sievert | 1,000 millisieverts |
| 1 millisievert | 1,000 microsieverts |
| 1 microsievert | 1,000 nanosieverts |
| 1 rem | 1,000 millirem |
| 1 millisievert | 100 millirem |
| 1 microsievert | 0.1 millirem |
| 1 millirem | 10 microsieverts |
| 1 microrem | 10 nanosieverts |
Frequently asked questions
How many rem are in one sievert?
One sievert equals exactly 100 rem. Multiply a sievert value by 100 to obtain rem.
How many sieverts are in one rem?
One rem equals 0.01 sievert. Divide a rem value by 100 to obtain sieverts.
Is one millisievert equal to 100 millirem?
Yes. One millisievert equals 100 millirem because both prefixes scale their parent units consistently.
Can this calculator convert dose rates?
It can convert the dose portion when the time basis remains unchanged. For example, Sv/h to rem/h uses the same factor of 100. Do not remove or change the time component unless you perform a separate time conversion.
Are sievert and gray interchangeable?
No. Gray measures absorbed dose, while sievert expresses equivalent or effective dose. Additional radiation and possibly tissue information may be required.
Why does the result show scientific notation?
Automatic formatting uses scientific notation for extremely small or large values. Select fixed decimal notation to force a decimal display.
Does more decimal precision mean greater accuracy?
No. Display precision only controls formatting. The uncertainty and significant figures of the original measurement still determine practical accuracy.
Is calculation history uploaded anywhere?
No. The history feature uses local browser storage. Clearing browser data or selecting “Clear history” removes it.
Accuracy and safety disclaimer
This calculator performs mathematical unit conversions and formatting. It does not diagnose radiation injury, classify an exposure as safe, replace calibrated instruments, establish legal compliance, or substitute for advice from a radiation-safety officer, health physicist, medical physicist, physician, regulator, or emergency authority.
Verify critical calculations independently and retain the original quantity, unit, time basis, measurement uncertainty, and source documentation. In an actual or suspected radiation incident, follow official emergency procedures and obtain qualified assistance.