Radiation Dose Rate Calculator

Enter a documented gamma dose-rate constant, activity, distance and time to estimate dose-equivalent rate and total dose for an ideal unshielded point source.

Use the Radiation Dose Rate Calculator

Source Parameters

Use the value and dose quantity stated by your authoritative reference.

Enter source parameters and click Calculate to see results.

Educational estimate only. Do not use for medical treatment, shielding design, emergency response, worker release, or regulatory compliance. The model assumes an unshielded point source and omits scatter, buildup, source geometry and decay during exposure. Consult a qualified health or medical physicist.

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Summary

This educational calculator applies the inverse-square point-source model Ḣ = A × Γ / r². You must supply a gamma dose-rate constant from a source appropriate to the radionuclide and dose quantity. It does not model shielding, scatter, source geometry, buildup, decay during exposure, or patient dose.

How it works

  1. Obtain a gamma dose-rate constant from a documented source and enter it in µSv·m²/(MBq·h).
  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 ideal point-source equation: dose-equivalent rate = activity × gamma constant / distance².
  6. Total dose is computed as Dose Rate × Exposure Time, then displayed in your chosen unit.

Use cases

  • Academic and training exercises on inverse square law calculations.
  • Checking hand calculations against a documented point-source example.
  • Converting a dose-equivalent estimate between µSv, mSv, and mrem.

Frequently Asked Questions

Last updated: 2026-09-30 · Reviewed by Nham Vu