Support

Questions, bug reports, wrong numbers, and feature requests all go to the same place. No account needed.

Reporting a number you think is wrong? Please include the isotope or material, every input you entered with its units, the value the app showed, and the value you expected with its source. That turns a report into something reproducible, and accuracy reports get looked at first.

Common questions

OFFLINE: Every calculator works with no network connection. All reference data ships inside the app — nothing is fetched while you use it.
ACCOUNTS: There are none. No sign-up, no login, no password to lose.
COST: Every feature in the current release is free and unrestricted.
UNITS: Switch between SI and US customary from the settings control — becquerels or curies, sieverts or rem. It changes display only, never the underlying maths.
BROWSER: The version on this site is the same codebase as the mobile apps. The mobile builds are smoother for gestures such as pinch-zooming the chart of nuclides.

Where the numbers come from

Every dataset in the app is published by a public scientific authority, and every screen cites its source and the textbook section its formulas come from.

NUCLIDES: IAEA Live Chart of Nuclides — 3,383 ground states from the NUBASE2020 and AME2020 evaluations.
GAMMA LINES: IAEA decay radiation data (ENSDF) — emission energies and intensities.
SHIELDING: NIST Standard Reference Database 126 — photon mass attenuation and energy-absorption coefficients (Hubbell & Seltzer).
DENSITIES: PubChem, National Center for Biotechnology Information (NCBI/NIH).
FORMULAS: Lamarsh & Baratta, Introduction to Nuclear Engineering; Duderstadt & Hamilton, Nuclear Reactor Analysis; ICRP Publications 74 and 103.

A note on scope. Nuclear Toolkit is a reference and calculation tool for people who already work in the field. It is not a medical device, it does not read from or control any instrument, and its results are not a substitute for qualified health physics or nuclear engineering analysis. See the Terms of Service for the full statement.