Radiation Dose Rate Calculator

Calculate radiation dose rate and total accumulated dose from source activity, distance, and exposure time, with unit conversion between mSv, mrem, mGy, and rad.

Source Parameters

Enter source parameters and click Calculate to see results.

This tool is for educational and planning purposes only. Results assume an unshielded point source in air using the inverse square law. Consult a qualified medical physicist or health physicist for clinical, occupational, or regulatory decisions.

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Summary

Calculate radiation dose rate and total accumulated dose from source activity, distance, and exposure time, with unit conversion between mSv, mrem, mGy, and rad.

How it works

  1. Select a common radioactive isotope or enter a custom gamma factor.
  2. Enter the source activity in MBq or mCi.
  3. Enter the distance from the source in meters or feet.
  4. Enter the exposure time in hours, minutes, or seconds.
  5. The calculator applies the inverse square law: Dose Rate = Activity × Gamma Factor / Distance².
  6. Total dose is computed as Dose Rate × Exposure Time, then displayed in your chosen unit.

Use cases

Frequently Asked Questions

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Last updated: 2026-05-23 · Reviewed by Nham Vu