Sequence Property Calculator

Paste or upload multi-FASTA sequences—DNA, RNA, or protein. The tool detects each sequence type automatically and builds a sortable table of molecular weight, length, GC%, pI, extinction coefficients, GRAVY, and instability index. Toggle average or monoisotopic mass, linear or circular topology, and single- or double-strand settings for nucleic acids. Results update as you type—no submit button.

Click any row to convert mass or A260/A280 readings into molarity, mass concentration, and copy number using that sequence's MW and extinction coefficient. Export the full table to CSV, copy rows for Excel, or share a permalink. Dilution and ligation tabs plan serial dilutions and calculate insert mass for cloning setups.

ExPASy ProtParam handles protein only, one sequence at a time, with no CSV export. DNA calculators like SMS2 cover nucleic acids but not proteins, and still lack batch tables. Researchers often paste values into Excel by hand or write Python scripts for mixed FASTA files.

This browser tool accepts mixed DNA, RNA, and protein FASTA in one session, updates live as you paste, and exports a full results table. Row-level concentration math uses each sequence's computed MW and extinction coefficient. Dilution and ligation planning sit in the same workspace—no install or account.