Choose molecular mass, base-pair length, or mass per base pair and enter the two known quantities. Units include bp, kbp, Mbp and Da, kDa, MDa, g, or kg. Mass refers to one molecule, not a bulk DNA sample.

Estimate the mass of one double-stranded DNA molecule. The default is an average 650 Da per base pair, not an exact sequence-specific mass.

Positive length in bp, kbp or Mbp. Fractional values may represent an average or estimate.

650 Da/bp is the documented default for approximate dsDNA calculations. Replace it with a justified factor when needed.

Result unit

Related Calculators

Base Pair to Dalton Formula

The following formula is used to calculate the molecular weight in Daltons for a given number of base pairs.

D = BP × CF

Variables:

  • D is the molecular weight in Daltons
  • BP is the number of base pairs
  • CF is the conversion factor (Daltons per base pair)

To estimate molecular mass in Daltons, multiply the number of base pairs by the conversion factor. The default 650 Da/bp is an average approximation for double-stranded DNA; actual mass depends on composition, ends, counterions and modifications. Gram and kilogram conversions use 1 Da ≈ 1.66053906892 × 10⁻²⁷ kg (2022 CODATA).

Base Pairs to Daltons Conversion Table (650 Da per bp)
Base Pairs (bp) Daltons (Da)
1650
21300
53250
106500
159750
2013000
2516250
3019500
4026000
5032500
7548750
10065000
15097500
200130000
250162500
300195000
500325000
750487500
1000650000
20001300000
*Assumes average 650 Da per base pair. Actual mass varies with base composition and modifications.

What is a Dalton?

A Dalton, also known as an atomic mass unit (amu), is a standard unit of mass that quantifies mass on an atomic or molecular scale. It is defined as one twelfth of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state, and it is approximately equal to the mass of one nucleon (either a single proton or neutron). The Dalton is used in biochemistry and molecular biology to express the mass of large molecules such as proteins and nucleic acids.

How to Calculate Base Pair to Dalton?

The following steps outline how to calculate the molecular weight in Daltons from the number of base pairs.

  1. First, determine the number of base pairs (BP).
  2. Next, use the default average factor of 650 Da/bp for approximate double-stranded DNA calculations, or enter a justified custom factor.
  3. Finally, calculate the molecular weight in Daltons using the formula D = BP * CF.
  4. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Number of base pairs (BP) = 1000

Conversion factor (CF) = 650 Daltons per base pair; estimated mass = 650,000 Da per molecule