Radiation Units & Ionizing Dose Converter

Radiation Units, Dosimetry & Biological Risk Metrology

Radiation quantities are divided into three distinct physical categories: Absorbed Dose (energy deposited), Equivalent/Effective Dose (biological risk), and Radioactivity (decay rate):

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• Universal Radiation Dose Equivalent Formulas (SI & Traditional)**:

1 Sievert (Sv) = 100 Rem (rem) = 1,000 mSv = 10^6\ μSv = 100,000 mrem

1 Millisievert (mSv) = 100 Millirem (mrem) = 0.10 rem = 1,000\ μSv = 10^-3 Sv

1 Rem (rem) = 0.010 Sv = 10 mSv = 1,000 mrem | 1 mrem = 10\ μSv = 0.010 mSv

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• Absorbed Dose & Radiation Quality Formulas**:

H = D × w_R

1 Gray (Gy) = 1 J/kg = 100 Rads (rad) = 1,000 mGy | 1 rad = 0.010 Gy = 100 erg/g

w_R = 1.0, w_R = 2.0 to 20 (Neutrons), w_R = 20 (Alpha particles)

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• Standard Radiation Dose Benchmarks (ICRP 103)**:

• Single Dental / Chest X-Ray: 0.01 to 0.10 mSv = 1 to 10 mrem Minimal diagnostic dose

• Annual Natural Background: 2.40 mSv/year = 240 mrem/year Radon, cosmic, terrestrial

• Head CT Scan: 2.00 mSv = 200 mrem = 0.20 rem Standard diagnostic imaging

• ICRP Occupational Limit: 20.0 mSv/year = 2.0 rem/year Nuclear/medical worker safety ceiling

• Acute Radiation Sickness (ARS): 1.0 Sv (100 rem) Threshold for temporary nausea, lymphocyte drop

How to Use This Calculator

Enter your Radiation Dose / Activity Magnitude (e.g. 2.0 in val), From Radiation Unit — choose from Millisieverts (mSv = 10⁻³ Sv = 100 mrem - Dose Equivalent), Microsieverts (µSv = 10⁻⁶ Sv = 0.1 mrem), Sieverts (Sv = 1 J/kg = 100 rem - SI Dose Equivalent), To Radiation Unit — choose from Millirem (mrem), Millisieverts (mSv), Microsieverts (µSv), Radiation Quality / Weighting Factor (w_R) (e.g. 1.0 for Gamma/X-ray/Beta, 20 for Alpha in w_R), and ICRP & Nuclear Medicine Benchmark — choose from Custom Radiation Dose, Standard Chest X-Ray (0.10 mSv = 100 µSv = 10 mrem), Global Average Natural Background (2.40 mSv/yr = 240 mrem/yr). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Conversion factors (to SI base unit or reference unit):

val: 0.10

wr: 1.0

maximumFractionDigits: 4

Worked Example

A medical physicist reviewing a patient's CT scan protocol converts a 2.0 mSv organ dose into 200 mrem to communicate clearly with clinical staff trained in traditional units, verifying the dose remains well below diagnostic reference levels.

Understanding Your Result

Unit conversions are exact by definition within a given measurement system (e.g., 1 km = exactly 1,000 m). Cross-system conversions (metric to imperial) use defined exchange factors: 1 inch = exactly 2.54 cm; 1 pound = 0.45359237 kg. Round your converted result to match the precision of your original measurement — expressing more decimal places than your input justifies implies false accuracy. For regulatory, legal, or safety-critical applications, verify which measurement system is required by the applicable standard.