Radiation Dose Calculator
Pick a tritiated-water concentration from the news — Fukushima, Indian Point, Monticello — and see the radiation dose it actually delivers, next to bananas, flights, and other everyday exposures.
1 · Pick a tritium concentration
2 · How much did you drink?
Delivered over weeks as the tritium leaves your body, not all at once — tritium’s biological half-life is only ~10 days.
That’s the same dose as…
Estimated added cancer risk (LNT upper bound)
The Linear No-Threshold (LNT) model almost certainly overstates risk at doses this low — it is a maximum credible upper bound, shown because regulators use it. Add it to the ~40% baseline chance any person is diagnosed with some cancer in their lifetime. Basis: ICRP-103 — 1 Sv whole-body ≈ 5.5% added lifetime risk.
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“Drinking 1 gallon(s) of water at 5,625 pCi/L tritium = 0.0014 mrem — about 0.14 bananas. via tools.genatom.org”
How this works
Tritium (³H) is a very weak beta emitter — just 18 keV, versus the ~1,300 keV betas and gammas from the potassium-40 (⁴⁰K) naturally inside your body. It has a ~12-year physical half-life but only a ~10-day biological half-life, so most of any tritium you ingest leaves your body before it can deposit its decay energy.
The dose is computed straight from the ICRP tritiated-water (HTO) ingestion coefficient:
dose[Sv] = concentration[Bq/L] × water[L] × 1.73e-11 Sv/Bq pCi/L → Bq/L : × 0.037 gallons → L : × 3.78541
This calculator uses the coefficient from the original tool’s source sheet (1.73e-11 Sv/Bq). The current ICRP-103 published value is 1.80e-11 Sv/Bq (~4% higher).
Sources: dose math & reference constants — LLNL ASER (1999) Appendix A; ICRP Publication 103 (2007); EPA drinking-water limit; NRC Monticello report. Comparison doses (bananas, X-rays, flights, CT, K-40, ISS, Denver) transcribed from Generation Atomic’s original tritium-dose spreadsheet.
Built by Generation Atomic.