About
Biology tools are scattered across hundreds of websites, and a great many of them are unsourced. You get a number with no indication of which formula produced it, which model it assumed, or whether anyone ever checked it.
Biology 101 is an attempt at the opposite. There are 33 tools here so far, and every one of them shows the expression it evaluated, names the model where more than one is accepted, and links to the source that formula comes from. A tool that cannot fill that in does not ship.
Nothing you enter leaves your browser
Every calculation runs locally, on your device. Sequences, constructs and concentrations are never uploaded, never logged and never stored on a server — there is no server. The site is a set of static files, and the arithmetic happens in the page.
This matters most for unpublished work. Pasting a proprietary construct into an unfamiliar website is a reasonable thing to be uneasy about, and the honest fix is not a privacy policy but an architecture where the data has nowhere to go.
How the numbers are checked
Each tool’s calculation is tested against reference values — figures from the literature, from standards bodies, or from established tools — and those tests run on every change. Where a discrepancy is unavoidable, it is stated on the page rather than hidden. Molar masses, for instance, follow IUPAC’s current abridged atomic weights, which can differ from a supplier’s catalogue in the last digit.
Where the science admits more than one accepted method, the choice is yours and the consequence is visible. Melting temperature is the clearest case: basic, salt-adjusted and nearest-neighbour models disagree, and a calculator that silently picks one is hiding the most important thing about its answer.
Results are for planning. Verify anything critical independently — and if you find a number that is wrong, please report it. That is the most useful thing anyone can send us.
Open source
The site is MIT licensed. Anyone can read the code that produced a result, which is the only real way to make “shows its work” mean something. Third-party code and data are credited with their licences in the repository.
What’s next
The catalogue is early. Tools marked as planned are announced rather than built, and they are listed openly because a visible gap is more useful than a dead link. Which of them gets built next depends largely on what people arrive here looking for.