Worked example
For a 4,000 bp vector, 1,000 bp insert, 50 ng vector, and 3:1 insert:vector molar ratio, the plan uses approximately 18.94 fmol vector and 56.82 fmol insert; the required insert mass is 37.5 ng.
Cloning
DNA Insert:Vector Ligation Calculator
Calculate vector and insert femtomoles, masses, volumes, molar-ratio comparisons, and optional reaction capacity without assuming a vendor-specific recipe.
Calculations run locally in your browser. Values are only placed in a URL when you choose “Copy Shareable Link.”
How to use
- Enter vector and insert lengths and concentrations.
- Choose the desired insert:vector molar ratio and vector mass.
- Compare vector and insert amounts in fmol to verify molar normalization.
- Optionally reserve reaction capacity, then review the ratio comparison and bench record.
Assumptions
The generic stoichiometry assumes vector and insert are double-stranded DNA and uses 660 g/mol per base pair to estimate femtomoles. Ratios are always labeled Insert : Vector.
Validation and limitations
Femtomole amounts are molecular-weight estimates. Common ratios are starting points, not guarantees. The calculator does not select ligase, buffer, enzyme amount, temperature, or incubation time and does not replace a validated kit protocol or laboratory SOP.
Related calculators
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Save calculations and run timed protocols with RayCrest Lab Calculator on iPhone, iPad, and Apple Watch.
Design, annotate, and verify the resulting plasmid.
Continue from ligation stoichiometry into cloning and sequence verification in RayCrest MDS.