Free · Laboratory calculations

DNA Insert Mass from Vector Mass & Molar Ratio

Calculate insert DNA mass from vector mass, fragment lengths and a chosen insert-to-vector molar ratio, with bp/kb and mass unit choices.

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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

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Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

For a 1 kb insert, 5 kb vector, 50 ng vector mass and 3:1 insert-to-vector molar ratio, the corresponding insert mass is 30 ng.

Insert mass = vector mass × (insert length / vector length) × insert:vector molar ratio

Worked example

Enter these known values and leave the other values blank.

Insert fragment length
1 kb
Vector fragment length
5 kb
Vector DNA mass
50 ng
Insert-to-vector molar ratio
3:1
Corresponding insert DNA mass
30 ng

Assumptions and limitations

  • Both fragment lengths and masses are positive. The length correction assumes comparable double-stranded DNA mass per base pair.
  • The ratio describes molecule counts, not equal DNA masses. A shorter insert needs less mass for the same molecule count.
  • The available molar-ratio choices are 1:1, 2:1, 3:1, 5:1 and 7:1. Select the ratio appropriate to your existing protocol.
  • This tool calculates mass balance; it does not predict reaction yield or select experimental conditions.

Common questions

Why does fragment length affect the mass?

At comparable mass per base pair, longer fragments have more mass per molecule. The length ratio converts a molecule-count ratio into a mass ratio.

Can I solve for vector mass instead?

Yes. Supply insert mass, both fragment lengths and the selected molar ratio; the calculator can recover vector mass.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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