Free radiation safety tools
Quick, accurate calculators for radiation safety officers, nuclear medicine technologists and health physicists. Free, no sign-up, and nothing you enter leaves your browser.
Decay calculator
Activity remaining for any isotope between two times, forward or back. Tc-99m, F-18, I-131, Cs-137 and 30+ more.
Ci ↔ Bq converter
Ci, mCi, µCi, nCi, TBq, GBq, MBq, kBq, Bq and dpm, all at once, using the exact definitions.
Leak test calculator
Check a wipe test against the 0.005 µCi (185 Bq) action level in 10 CFR 35.67, from activity or from counts.
Decay-in-storage calculator
Earliest survey date for decay-in-storage waste under 10 CFR 35.92, at 10 half-lives or your license's minimum.
Accurate and checked
Every half-life comes from NNDC/ENSDF evaluated nuclear data, and unit conversions use the exact definition 1 Ci = 3.7 × 1010 Bq. Regulatory limits are quoted from 10 CFR Parts 20 and 35. CurieLedger tests these values automatically every time the tools change.
More in the free demo
The CurieLedger demo also includes a regulations library, a radioactive materials shipping and receiving reference, and Find an RSO.