Caffeine exact mass
Calculate the average and monoisotopic masses of caffeine.
Molecular Weight Calculator
FigranEnter a formula or a DNA or RNA sequence to get its molecular weight and exact mass.
- Hydrates and isotopes
- Exact mass and adducts
- DNA and RNA
C8H10N4O2
Molecular weight194.19 g/mol
Monoisotopic mass194.0804 Da
Hill formula: C8H10N4O2 · 24 atoms
Composition
| Element | Count | Atomic weight | Mass (g/mol) | Mass % |
|---|---|---|---|---|
| C | 8 | 12.01100 | 96.09 | 49.48% |
| H | 10 | 1.00800 | 10.08 | 5.19% |
| N | 4 | 14.00700 | 56.03 | 28.85% |
| O | 2 | 15.99900 | 32.00 | 16.48% |
Adduct ions
| Ion | Charge | m/z |
|---|---|---|
| [M+H]⁺ | 1 | 195.0877 |
| [M+Na]⁺ | 1 | 217.0696 |
| [M+K]⁺ | 1 | 233.0435 |
| [M+NH₄]⁺ | 1 | 212.1142 |
| [M+2H]²⁺ | 2 | 98.0475 |
| [M]⁺• | 1 | 194.0798 |
Molecular weight calculator examples
Start with an example and adapt it to your research.
CuSO₄·5H₂O molar mass
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Buffer reagents in one list
Calculate a list of reagents together.
M13 forward primer
Find the mass of a single-stranded DNA primer.
let-7a microRNA
Calculate an RNA with a 5′ phosphate.
pUC19 plasmid, µg to pmol
Estimate a double-stranded plasmid from its length.
How to calculate molecular weight
Calculate molecular weight in four steps.
1Choose a mode
Select a formula or a DNA or RNA sequence.
2Enter your input
Paste a formula or sequence; use one formula per line.
3Read the results
Compare molecular weight, exact mass and ions.
4Save the result
Copy the results or export a CSV.
Molecular weight vs exact mass
Use average molecular weight for weighing and monoisotopic mass for small-molecule HRMS.
| Example | Formula | MW (g/mol) | Monoisotopic mass (Da) | Nominal mass (Da) | [M+H]⁺ m/z |
|---|---|---|---|---|---|
| Caffeine | C8H10N4O2 | 194.19 | 194.0804 | 194 | 195.0877 |
| Reserpine | C33H40N2O9 | 608.69 | 608.2734 | 608 | 609.2807 |
| Glucose-13C6 | 13C6H12O6 | 186.11 | 186.0835 | 186 | 187.0908 |
| Copper sulfate pentahydrate | CuSO4·5H2O | 249.68 | 248.9342 | 249 | — |
Mavg = Σ nᵢ Aᵣ,ᵢ
Mmono = Σ nᵢ mᵢ
m/z = (Mmono + Σmadduct − z me) / |z|
References: CIAAW · NIST · JOC Author Guidelines
DNA and RNA molecular weight
Terminal groups and strand count change the calculated molecular weight.
| Example | Convention | MW (g/mol) |
|---|---|---|
| M13F · 17 nt | 5′-Hydroxyl | 5228.47 |
| M13F · 17 nt | 5′-Phosphate | 5308.45 |
| M13F · 17 nt | 5′-Triphosphate | 5468.40 |
| pUC19 · 2686 bp | This calculator · 5′-OH | 1,659,553 ≈ 1.66 MDa |
| pUC19 · 2686 bp | NEB · 617.96 g/mol/bp | 1,659,841 ≈ 1.66 MDa |
| pUC19 · 2686 bp | Thermo · 607.4 g/mol/bp + 157.9 | 1,631,634 ≈ 1.63 MDa |
| pUC19 · 2686 bp | 650 g/mol/bp · sodium salt | 1,745,900 ≈ 1.75 MDa |
pmol = µg × 10⁶ / MW
References: OligoCalc · NEB Nucleic Acid Data · Thermo Fisher
Molecular weight calculator FAQ
How do I calculate molecular weight from a chemical formula?
Multiply each atom count by its standard atomic weight, then add the results. Caffeine has a molecular weight of 194.19 g/mol.
Is molecular weight the same as molar mass?
Their numerical values correspond: relative molecular mass is dimensionless, while molar mass is expressed in g/mol.
How do I enter hydrates, brackets and isotopes?
Use CuSO4·5H2O, CuSO4*5H2O or CuSO4.5H2O; nested brackets and labels such as [13C]6 are supported. Element symbols are case-sensitive. You can also enter common reagent names. SMILES input is not supported. To obtain a formula from a structure, use the Chemical Structure Drawer.
Which mass should I use for mass spectrometry?
Use monoisotopic mass for small-molecule HRMS and average molecular weight for weighing.
How are adduct m/z values calculated?
Add the mass of the ionizing species and divide by the absolute charge. Electron mass is included.
How do I report HRMS data in a paper?
Report the calculated ion formula and m/z with the observed value. Use Export → Copy HRMS & elemental analysis to create a starting point.
Why do DNA molecular weight calculators give different values?
Terminal groups, strand count, base composition and salt form change the result. This calculator uses a 3′ hydroxyl end and does not include sodium salts.
How do I convert grams to moles or DNA mass to copies?
Divide mass by molecular weight to obtain moles; multiply moles by Avogadro’s constant for copies. For solution preparation, use the Molarity Calculator.
Can I calculate peptide or primer properties here?
This calculator handles DNA and RNA molecular weight; protein sequences and primer melting temperatures have separate tools. Protein Molecular Weight Calculator · Primer Tm Calculator.
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