RNA Molecular Weight Calculator
Calculate the molecular weight of an RNA molecule and convert mass to moles.
About RNA Molecular Weight Calculator
RNA nucleotides average 321.5 daltons, marginally different from DNA because ribose carries an additional hydroxyl. The mass-to-mole conversion is essential for setting up in vitro transcription and transfection. Molar amount rather than mass determines how many transcripts are delivered, which is what actually drives expression level.
Formula
RNA Molecular Weight
MW ≈ 321.5 × nucleotides + 159 for single-stranded RNA
- 321.5 Da
- Average mass of a ribonucleotide, slightly above DNA because of the extra oxygen
Worked example
With the default values below, RNA Molecular Weight Calculator returns Molecular Weight of 321,659.00. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Length in nucleotidesminimum 0 nt
- 1,000 nt
- Quantity availableminimum 0 ug
- 10 ug
- Average mass per nucleotideminimum 1 Da
- 321.5 Da
Results
- Molecular Weight
- 321,659.00 Da
- Amount
- 31.0888 pmol
- Number of Molecules
- 18,722,127,346,040
- Conversion Factor
- 321.6590 ug/nmol
- Length
- 1.0000 kb
Step by step
- 1Values used
- 2RNA Molecular Weight
- 3Molecular Weight= 321,659.00 Da
- 4Amount= 31.0888 pmol
- 5Number of Molecules= 18,722,127,346,040
- 6Conversion Factor= 321.6590 ug/nmol
- 7Length= 1.0000 kb
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is RNA Molecular Weight calculated?
MW ≈ 321.5 × nucleotides + 159 for single-stranded RNA RNA nucleotides average 321.5 daltons, marginally different from DNA because ribose carries an additional hydroxyl. The mass-to-mole conversion is essential for setting up in vitro transcription and transfection.
Why does RNA Molecular Weight matter?
Molar amount rather than mass determines how many transcripts are delivered, which is what actually drives expression level.
What values do I need to enter?
This calculator takes 3 inputs: Length in nucleotides, Quantity available, Average mass per nucleotide. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.