Direct answer
The DNA double helix is about 2 nm in diameter. This value describes its width; the length of a DNA molecule depends on how many base pairs it contains and how it is packaged.
Representative value2 nm
In meters2 × 10⁻⁹ m
Measurement typeTypical diameter
Put it in context
What are we measuring at this scale?
Two nanometers is twice the one-nanometer marker and many times a characteristic atomic dimension. DNA is a molecule, not a smooth solid rod, so the illustration shows structure rather than a hard boundary.
Scientific visualization
DNA double helix
The double helix is about two nanometres in diameter.
Source and verification
Where the value comes from
National Human Genome Research Institute
ScaleTrip keeps the 2 nm range and the typical diameter label visible together.