How to use (3 steps)
- Select nucleic acid type (dsDNA, etc.) and length (bp/nt).
- Enter one known value among ng/µL, nM, or copies/µL.
- Other values are calculated automatically. Enter volume to see totals.
Input (type, length, concentration)
Results (ng/µL, nM, copies)
Results will appear here.
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How it’s calculated
- Molecular weight = length × factor (approx.)
mol/L = g/L ÷ molecular weightcopies/L = mol/L × Avogadro's constant- Entering volume yields total ng, total pmol, and total copies.
FAQ
What is 10 ng/µL in nM?
It depends on fragment length and nucleic acid type. The same 10 ng/µL gives a much higher nM value for a short fragment than for a long amplicon or transcript.
How are copy numbers calculated?
The tool converts mass concentration to molar concentration through molecular weight, then multiplies the molar amount by Avogadro's constant to get copies.
Why do factors differ between dsDNA and RNA?
Average molecular weight per base or base pair differs by nucleic acid type. This tool uses standard approximate factors for dsDNA, ssDNA, RNA, and oligos.
Can I convert without length (bp/nt)?
Length is needed to estimate molecular weight. If you know the exact molecular weight, enter it directly as g/mol.
What does entering volume show?
It calculates total mass, total pmol, and total copies in the entered volume, which is useful for tube totals, aliquots, and dilution planning.
What does the share URL include?
It restores input values (type, length, units, etc.).
How to choose the right output first
For qPCR and standards
If you are preparing standards or template estimates, copies/µL is often the target output. Start from ng/µL or nM, then convert to copies/µL only after confirming fragment length and whether the molecule is dsDNA, ssDNA, or RNA.
For NGS and dilution workflows
If you are pooling libraries or targeting equal molar input, nM is usually the output you need first. Convert from ng/µL using the fragment length that matches the actual insert or library size distribution used in the workflow.
For quick sanity checks
If another tool gives a very different answer, compare the fragment length, nucleic acid type, and molecular-weight convention first. Check those assumptions before deciding one result is wrong.
Related tools
- NGS library concentration (ng/µL → nM) | dilution | CalcBEConvert library mass concentration to nM, then check dilution and pooling targets for sequencing prep.
- A260 Calculator (DNA/RNA Concentration & Purity) | CalcBEEstimate nucleic-acid concentration and purity from absorbance before converting to molar or copy-based units.
- DNA assembly mix calculator (Gibson/Golden Gate) | CalcBEPlan backbone and insert amounts after converting your stock concentrations to a comparable molar basis.
- qPCR standard curveTurn copy-number assumptions into standard-curve checks and dilution-series planning for qPCR runs.
- Centrifuge converter (rpm ↔ RCF ×g) | by rotor radius | CalcBECheck centrifuge settings alongside sample-prep steps when you move between concentration and cleanup workflows.
Feedback
Let us know issues or improvement ideas to help refine this tool.