Peptide Research Tools is a free set of bench calculators for peptide and solution work: molecular weight, sequence properties, moles, molarity, dilutions, concentration units and stock solutions. There are 12 tools so far, each paired with a guide that explains the calculation.
Why it exists
Most lab calculation errors are not hard maths. They are a unit off by 1000, a forgotten water molecule, or a net-content correction applied twice. Calculators that only print an answer hide those mistakes. Every tool here shows the formula, the working with your own numbers, and the sources for its constants, so you can check a result before you rely on it.
What we hold ourselves to
- Shown, not hidden. Every result comes with the equation and the substituted values.
- Sourced. Atomic weights, residue formulas, pKa sets and extinction coefficients come from IUPAC, NIST and the original papers. Each tool lists its sources, and the methodology page lists every constant.
- Private by design. Calculations run in your browser. The values you enter are not sent to our server.
- Corrected in the open. If you find an error, tell us. We fix it, note the change and credit the reporter if they wish.
Who it is for
Researchers, technicians and students who prepare solutions, and educators who teach the maths behind them. The guides are written to be linked from course pages and lab wikis, and the calculators can be embedded with one line of code.
Support and independence
Peptide Research Tools is supported by NuLife Peptides. The sponsor has no input into the calculators, the guides or their sources, and there are no product links in the tools. Details are on the sponsors page.
Use, link and embed
You are welcome to link to any tool or guide, cite them in methods sections or teaching material, and embed calculators on your own pages with the embed code on each tool. A link back is all we ask.