DNA Copy Number Calculator

Find the number of DNA molecules in a sample.

Copies (molecules) 30,882,773,128.21

Formula: copies = mass(g) × 6.022e23 ÷ (length × 650)

Step-by-step with your numbers:

1. Values used:

2. DNA mass = 100 ng

3. DNA length = 3,000 bp

5. Copies = 30,882,773,128.21molecules

Did we solve your problem today?

Convert a DNA mass into the number of molecules (copies).

The math behind it

copies = mass (g) × Avogadro's number ÷ (length in bp × 650 g/mol per bp).

100 ng of 3 kb DNA → ~3.1 × 10¹⁰ copies.

Why 650?

The average molar mass of one base pair of double-stranded DNA is ~650 g/mol.