External Radiation Dose Calculator
Estimate cumulative external radiation dose (mSv) from a dose rate (µSv/h) plus exposure hours and days. Shows the annualized dose and a comparison with the 1 mSv/year public limit.
Input
Estimate cumulative external radiation dose from a dose rate (µSv/h) and exposure time. Enter the dose rate shown on your dosimeter or published by a monitoring post. Results are approximate; for health-related decisions, refer to official agency information.
Result
Cumulative dose (estimate)
0.055mSv
= 55.2 µSv (total exposure 240 h)
Annualized (same conditions for 365 days)
0.672 mSv/year
Dose per day
1.84 µSv/day
Annual public limit (reference)
1 mSv/year
The annualized dose is about 67.2% of the annual limit for additional public exposure (1 mSv/year), excluding natural background radiation.
Calculation breakdown
| Total exposure time | 240 h |
| Cumulative dose (µSv) | 55.2 µSv |
| Cumulative dose (mSv) | 0.055 mSv |
| Dose per day | 1.84 µSv/day |
| Annualized (365 days) | 0.672 mSv/year |
How it works
- The cumulative dose is calculated as 'cumulative dose (µSv) = dose rate (µSv/h) × exposure time (h)', where exposure time = 'hours per day (h/day) × number of days'.
- Unit conversion uses 1 mSv = 1000 µSv, and the headline cumulative dose is shown in millisieverts (mSv).
- The annualized figure assumes the daily dose continues for 365 days; if conditions vary, the actual dose will differ.
- 1 mSv/year is shown for reference as the typical annual limit for additional public exposure. It excludes natural background and medical exposure.
- This tool estimates external exposure only and does not account for internal exposure or dose coefficients that depend on the type of exposure.
- Results are only a rough guide. For assessing health effects or radiation protection, refer to official sources such as the Ministry of the Environment and the Nuclear Regulation Authority.
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