# Radiation Units and Conversion Factors

## International System of Units (SI) Unit and Common Unit Terminology

SI Units* Common Units
Dose Equivalent sievert (Sv) rem
Exposure coulomb/kilogram (C/kg) roentgen (R)

* SI Units: International System of Units

Note: In the table above the common units and SI units in each row are not equivalent in value, i.e., 1 curie does not equal 1 becquerel, but they both measure the same parameter.
See Conversion Equivalence

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## Conversion Equivalence

 1 curie = 3.7 x 1010 disintegrations per second 1 becquerel = 1 disintegration per second 1 millicurie (mCi) = 37 megabecquerels (MBq) 1 rad = 0.01 gray (Gy) 1 rem = 0.01 sievert (Sv) 1 roentgen (R) = 0.000258 coulomb/ kilogram (C/kg) 1 megabecquerel (MBq) = 0.027 millicuries (mCi) 1 gray (Gy) = 100 rad 1 sievert (Sv) = 100 rem 1 coulomb/ kilogram (C/kg) = 3,880 roentgens

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## Prefixes Often Used with SI Units

 Multiple Prefix Symbol 1012 tera T 109 giga G 106 mega M 103 kilo k 10-2 centi c 10-3 milli m 10-6 micro μ 10-9 nano n

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## Dose Unit Conversion Tool

Insert a number with up to 2 decimal points

### Dose Equivalent

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Insert a number with up to 2 decimal points
Results are expressed in E-notation*

*E-notation examples:
3.05e+9 = 3.05 x 109
7.26e-3 = 7.26 x 10-3

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## Exposure Unit Conversion Tool

Insert a number with up to 2 decimal points
Results are expressed in E-notation*

*E-notation examples:
3.05e+9 = 3.05 x 109
7.26e-3 = 7.26 x 10-3

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## Conversion Factors

To convert from

To

Multiply by

Curies (Ci)

becquerels (Bq)

3.7 x 1010

millicuries (mCi)

megabecquerels (MBq)

37

microcuries (μCi)

megabecquerels (MBq)

0.037

milligrays (mGy)

0.01

millirems (mrem)

microsieverts (μSv)

10

milliroentgens (mR)

microcoulombs/kilogram (μC/kg)

0.258

To convert from

To

Multiply by

becquerels (Bq)

curies (Ci)

2.7 x 10-11

megabecquerels (MBq)

millicuries (mCi)

0.027

megabecquerels (MBq)

microcuries (μCi)

27

milligrays (mGy)

100

microsieverts (μSv)

millrems (mrem)

0.1

microcoulombs/kilogram (μC/kg)

milliroentgens (mR)

3.88

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## References

1. What is Radiation Dose? (2:03 min) (DOE/ORISE/REAC/TS)
2. Sievert (Wikipedia)