What you are given
- Mass (ng): 50
- Length (bp): 1000
Formula: pmol = ng x 1000 / (660 x bp)
Molecular biology
How do you calculate dNA: ng to pmol?
Convert a dsDNA mass to moles (and back) from its length. The relationship used is pmol = ng x 1000 / (660 x bp).
Worked example
Every number below is computed by the calculator, not typed in
The working
- Solve for moles:
pmol = mass_ng * 1000 / (660 * bp) - Substitute:
pmol = 50 * 1000 / (660 * 1000)=0.07576 pmol - Picomoles per nanogram:
1000 / (660 * bp)=0.001515 pmol/ng
1000 bp dsDNA: 0.07576 pmol.
What each symbol means
- n: Amount of dsDNA (pmol)
- m: Mass of dsDNA (ng)
- L: Length (bp)
A printable one-page version is on the formula sheet.
Try it yourself
Two problems, with the working revealed
Problem 1 DNA: ng to pmol
Work out the result for dNA: ng to pmol.
- Mass (ng): 400
- Length (bp): 5000
Show the answer and the working
5000 bp dsDNA: 0.1212 pmol.
- Solve for moles:
pmol = mass_ng * 1000 / (660 * bp) - Substitute:
pmol = 400 * 1000 / (660 * 5000)=0.1212 pmol - Picomoles per nanogram:
1000 / (660 * bp)=0.000303 pmol/ng
Open this in the calculator to change the numbers.
Problem 2 DNA: ng to pmol
Work out the result for dNA: ng to pmol.
- Mass (ng): 75
- Length (bp): 1000
Show the answer and the working
1000 bp dsDNA: 0.1136 pmol.
- Solve for moles:
pmol = mass_ng * 1000 / (660 * bp) - Substitute:
pmol = 75 * 1000 / (660 * 1000)=0.1136 pmol - Picomoles per nanogram:
1000 / (660 * bp)=0.001515 pmol/ng
Open this in the calculator to change the numbers.
Do it with your own numbers.
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