RNA Molecular Weight Calculator

Calculate the molecular weight of RNA sequences for laboratory applications

Input Parameters

Use U for uracil (RNA), not T

Nucleotide Molecular Weights

AMP (Adenosine)347.22 Da
UMP (Uridine)324.18 Da
GMP (Guanosine)363.22 Da
CMP (Cytidine)323.20 Da

Molecular Weight

4220.50 Da

4.221 kDa

Detailed Results

Length13 nt
MW (unmodified)4220.50 Da
GC Content53.8%
Extinction Coef. (260nm)144,100 M⁻¹cm⁻¹
Mass for 1 nmol4.221 µg
Mass for 1 pmol4.221 ng

Base Composition

3

Adenine

3

Uracil

4

Guanine

3

Cytosine

About RNA Molecular Weight

RNA molecular weight differs from DNA due to the presence of a 2'-hydroxyl group on the ribose sugar and uracil instead of thymine.

Key considerations:

  • RNA nucleotides are approximately 16 Da heavier than corresponding DNA nucleotides
  • Average MW per nucleotide: ~340 Da (vs ~330 Da for DNA)
  • 5' modifications like caps significantly increase the total molecular weight
  • Poly-A tails on mRNA add ~347 Da per adenosine