Ligation Calculator
Enter your vector mass, the vector and insert lengths in base pairs, and the molar ratio you want. The calculator gives the insert mass and picomole amounts. It is a calculation aid, not a protocol.
Last updated: September 25, 2026
Frequently asked questions
What does the molar ratio mean?
It is the number of insert molecules for every vector molecule. A ratio of 3 means three insert molecules per vector molecule.
Why calculate by molar ratio instead of mass?
Longer DNA weighs more per molecule, so equal masses of vector and insert contain different numbers of molecules. Ratios by molecule count are what matter for joining ends.
What ratio should I use?
That depends on your protocol and construct. Follow your kit or laboratory protocol; this tool just does the arithmetic for the ratio you enter.
How is this different from the DNA Concentration Calculator?
The DNA Concentration Calculator converts between concentration units. This tool works out how much insert to pair with a given vector amount.
How is this related to the DNA Copy Number Calculator?
Both use the same average 650 g/mol per base pair, but copy number converts mass to molecule count rather than planning an insert amount.
Does this include reaction volumes or incubation steps?
No. It calculates DNA amounts only. Reaction setup should come from your protocol.