Absorbed dose unit converter

This absorbed dose unit converter allows users to convert between commonly used absorbed dose units, including both SI units and legacy units that continue to appear in historical records, international guidance, calibration documentation, and training materials.

It is intended to support clear communication, sense-checking of values, and consistent interpretation of absorbed dose information across different regulatory, technical, and educational contexts.

What this calculator does

Absorbed dose is a measure of the energy deposited by ionising radiation in a material, expressed as energy per unit mass. It is independent of radiation type or biological weighting.

While the gray (Gy) and its sub-multiples are now the standard units used within UK and international radiation protection and radiological practice, older units such as the rad remain in use within legacy reports, equipment documentation, calibration certificates, and some non-UK publications.

This calculator provides straightforward conversion between absorbed dose units using accepted, fixed relationships between units.

Supported absorbed dose units

The calculator supports conversion between the following absorbed dose units:

  • gray (Gy)

  • milligray (mGy)

  • microgray (µGy)

  • nanogray (nGy)

  • rad

  • millirad (mrad)

  • microrad (µrad)

Conversions are based on the standard relationship:

1 Gy = 100 rad

Appropriate use

This calculator is suitable for use when:

  • reviewing legacy absorbed dose reports or historical records;

  • interpreting international publications, calibration certificates, or technical documentation;

  • converting absorbed dose values for communication or comparison purposes;

  • supporting education, training, and professional development activities.

It is not intended to replace formal dose assessment, dosimetry evaluation, instrument calibration, or regulatory submissions.

Important note

The results provided by this calculator are indicative only and assume idealised unit relationships. They do not account for uncertainty, measurement methodology, radiation quality, or exposure context.

Outputs should not be relied upon as the sole basis for compliance decisions, safety assessments, or technical justifications. Where required, advice should be sought from a competent Radiation Protection Adviser (RPA) or other suitably qualified professional.

Related guidance

Absorbed dose quantities and units are defined and discussed within internationally recognised guidance, including publications from the International Commission on Radiation Units and Measurements (ICRU). These concepts underpin the dosimetric framework adopted by the International Commission on Radiological Protection (ICRP) and are implemented within UK legislation and associated Approved Codes of Practice and guidance.

Users should ensure that absorbed dose values are interpreted within their correct technical, regulatory, and exposure context.

For advice on applying absorbed dose information within your organisation or regulatory framework, please contact RP Alba Ltd.