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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.”

Ligation inputs

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.

How to use

  1. Enter vector and insert lengths and concentrations.
  2. Choose the desired insert:vector molar ratio and vector mass.
  3. Compare vector and insert amounts in fmol to verify molar normalization.
  4. 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.

Calculation record

Methodology and scientific authority

Calculate insert mass and DNA volumes from an explicit insert:vector molar ratio and optional reaction capacity.

Engine
dna-ligation-stoichiometry 1.1.0
Content updated

Methodology

Calculates insert mass from vector mass, fragment lengths, and insert:vector molar ratio; dsDNA femtomoles use 660 g/mol per bp.

Inputs

  • vector and insert lengths
  • DNA concentrations
  • vector mass
  • insert:vector ratio
  • optional reaction volume

Outputs

  • vector and insert femtomoles
  • insert mass
  • DNA volumes
  • ratio table
  • reaction-capacity warning

Validation examples

These scientific fixtures are reproducible tests of the calculation engine, not build-only checks.

  • 4,000 bp vector, 1,000 bp insert, 50 ng vector, and 3:1 yields 37.5 ng insert. Test: neb-style-three-to-one
  • A 4 µL DNA requirement warns when only 3 µL remains in the reaction. Test: reaction-capacity

Assumptions and limitations

Assumptions

  • Vector and insert are modeled as dsDNA using 660 g/mol per bp.
  • Displayed ratios are always Insert : Vector.

Limitations

  • Stoichiometry does not predict ligation efficiency.
  • Ends, phosphorylation, topology, purity, enzyme chemistry, incubation, and transformation efficiency are outside the model.

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