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Radiation Unit Converter

Convert radiation units for source activity (Bq, Ci), exposure (R), absorbed dose (Gy, rad), and equivalent dose (Sv, rem) with precision.

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    ☢️ Overview: Convert Radiation Units Across Medical & Nuclear Applications

    Radiation measurements are split across four main categories:

    • Source Activity: Measures how many radioactive decays happen per second.
      • Becquerel (Bq): 1 decay per second (SI unit)
      • Curie (Ci): Legacy unit; 1 Ci = 3.7×1010 Bq
    • Exposure: Measures ionization in air (now largely historical).
      • Roentgen (R): 1 R = 2.58×10⁻⁴ C/kg
    • Absorbed Dose: Measures energy absorbed per unit mass.
      • Gray (Gy): SI unit = 1 joule/kg
      • Rad: Older unit; 1 rad = 0.01 Gy
    • Equivalent Dose: Adjusts absorbed dose by biological effect.
      • Sievert (Sv): SI unit for health effect of radiation
      • Rem: 1 rem = 0.01 Sv

    This converter allows precise switching between all these units—whether you're analyzing radiology reports, calibrating equipment, or checking regulatory limits.

    🧮 Formula & Methodology: How Radiation Units Are Converted

    Radiation units are grouped by physical property. Within each category, conversions follow a simple 2-step method: 

    Step 1: Normalize to SI base unit  
  SI_value = input × factor_from

Step 2: Convert to target unit  
  result = SI_value ÷ factor_to

    For example:

    • 1 Ci → Bq: 1 × 3.7×1010 = 3.7×10¹⁰ Bq
    • 100 rad → Gy: 100 × 0.01 = 1 Gy
    • 5 Sv → rem: 5 ÷ 0.01 = 500 rem

    ⚠️ Note: You cannot convert between categories (e.g., Gy ↔ Bq) without biological or physical context.

    📊 Example Conversions

    • 1 Ci → Bq: 1 × 3.7×1010 = 3.7×10¹⁰ Bq
    • 100 rad → Gy: 100 × 0.01 = 1 Gy
    • 5 Sv → rem: 5 ÷ 0.01 = 500 rem
    • 0.2 R → C/kg: 0.2 × 2.58×10⁻⁴ = 5.16×10⁻⁵ C/kg

    🔬 Common Use Cases for Radiation Unit Conversion

    • 🩻 Medical Imaging: CT scans and X-rays typically report doses in mGy and mSv
    • ⚛️ Nuclear Medicine & Therapy: Radioisotope activity in Bq or Ci
    • 🏗️ Radiation Protection: Regulatory bodies set occupational limits in mSv or rem
    • 🧪 Physics Labs: Experimental setups require accurate conversions between R, C/kg, and Gy

    ❓ Frequently Asked Questions

    What is the difference between gray and sievert?

    Gray (Gy) measures the amount of energy absorbed by tissue. Sievert (Sv) includes biological impact via a weighting factor. For X-rays, 1 Gy ≈ 1 Sv, but not for all types of radiation.

    Why use becquerel instead of curie?

    Becquerel (Bq) is the modern SI unit. 1 curie = 3.7×10¹⁰ Bq. Bq is preferred in scientific literature and international regulations.

    Can I convert roentgen to sievert?

    Only approximately, and context matters. Roentgen measures ionization in air, while sievert measures biological effect. A conversion requires assumptions about radiation type and medium.

    Is rad still used?

    Rad is largely obsolete but still appears in older medical and nuclear documentation. 1 rad = 0.01 Gy.

    What does 1 mSv mean?

    1 millisievert is a thousandth of a sievert and is commonly used in radiology to quantify low radiation doses like from chest X-rays or CT scans.

    Are these conversions linear?

    Yes, within each category. Conversions like rad → Gy or Sv → rem use constant multipliers. Between categories, conversions are not possible without additional physical context.

    What’s the typical radiation dose for a CT scan?

    Most CT scans deliver around 2–10 mSv depending on the body part and scan protocol.