Calculator inputs
Mass of one atom: kg ( g)
For atoms, total mass is kg (= g). This corresponds to moles.
Mass of one atom in atomic mass units: u
Mass of one atom: fg, total mass: fg. log10(mass per atom in kg): .
Calculation history
Each calculation can be stored in the table below. Use the CSV or PDF buttons to save your data for lab reports or assignments.
| # | Basis | Input value | Atoms | Mass/atom (kg) | Mass/atom (g) | Mass/atom (u) | Total mass (kg) | Moles |
|---|
Formula used
The mass of a single atom can be computed from molar mass or atomic mass using Avogadro's number NA = 6.02214076 × 1023 mol-1 and the atomic mass unit 1 u = 1.66053906660 × 10-27 kg.
-
From molar mass M (g/mol):
matom = (M / 1000) / NA [kg] -
From atomic mass in u:
matom = A × 1.66053906660 × 10-27 [kg] -
From mass number A (approximate):
matom ≈ A × 1.66053906660 × 10-27 [kg]
For N atoms, total mass is N × matom. The number of moles is given by n = N / NA.
How to use this calculator
- Select a calculation mode: molar mass, atomic mass, mass number, or element quick selection.
- Enter the required input data depending on the chosen mode.
- Specify the number of atoms you are interested in.
- Optionally open advanced options to set precision or extra outputs.
- Click "Calculate mass" to see mass per atom and total mass.
- Use "Add current result to table" to build a calculation history.
- Export your table with the CSV or PDF buttons for documentation.
Example data table
This table shows approximate masses of single atoms for some common elements, using standard atomic weights and the atomic mass unit relation.
| Element | Molar mass (g/mol) | Atomic mass (u) | Mass of one atom (kg) |
|---|---|---|---|
| Hydrogen (H) | 1.008 | 1.008 | 1.675 × 10-27 |
| Carbon (C) | 12.011 | 12.011 | 1.994 × 10-26 |
| Oxygen (O) | 15.999 | 15.999 | 2.656 × 10-26 |
| Iron (Fe) | 55.845 | 55.845 | 9.274 × 10-26 |
| Gold (Au) | 196.97 | 196.97 | 3.27 × 10-25 |
Why mass of a single atom matters
Knowing the mass of one atom helps bridge microscopic structure and macroscopic samples. It connects measurable lab quantities like grams and moles to individual particles in gases, liquids, solids, and complex mixtures.
Link between molar mass and atomic mass
For elements, molar mass in g/mol and atomic mass in u share the same numerical value. This calculator divides molar mass by Avogadro's number to obtain mass per atom in kilograms and grams with consistent units.
Using this tool with the Advanced Atom Calculator
Combine this page with the Advanced Atom Calculator when you also need total atoms in a sample. First compute mass per atom here, then use the other tool for formula parsing and atom counts.
Connecting to the Atomic Mass Calculator
If your element has multiple isotopes, use the Atomic Mass Calculator to obtain a precise weighted atomic mass. You can then enter that value in amu here to find the corresponding mass of a single atom.
Working alongside the Mole Mass Converter
The Mole Mass Converter Calculator focuses on converting between moles and grams. Use that tool for bulk sample conversions and this calculator to zoom in on the mass of individual atoms.
Practical classroom and lab applications
In teaching labs this calculator illustrates how unbelievably small atomic masses are. In research settings it offers quick checks on orders of magnitude when estimating nanoparticle counts, thin film coverage, or adsorption at surfaces.
Understanding unit choices for atomic mass
Atomic masses are often tabulated in unified atomic mass units (u). The calculator converts u to kilograms and grams using the atomic mass constant, letting you keep units consistent with other SI calculations in physics and chemistry.
Significant figures and rounding considerations
Use the advanced options to set significant figures in scientific notation. For high-stakes work, keep a copy of unrounded numbers and match the precision of input data such as molar masses, abundances, or measured sample sizes.
Frequently Asked Questions
1. What is the difference between atomic mass and mass of an atom?
Atomic mass is usually quoted in atomic mass units as a weighted average for isotopes. Mass of an atom here is that same quantity expressed in kilograms or grams for one particle.
2. Can I use this calculator for molecules as well as elements?
Yes. Enter the molar mass of a compound to obtain mass per particle. For complex formulas, you can first compute molar mass using your own data or a dedicated molar mass tool.
3. How does this differ from the Atomic Mass Calculator?
The Atomic Mass Calculator focuses on combining isotopic masses and abundances. This page takes a molar or atomic mass and converts it into mass per atom and totals for chosen particle counts.
4. Why are results shown in scientific notation?
Atomic masses in kilograms are extremely small, so scientific notation keeps values readable. You can change the number of significant figures in advanced options to match your reporting needs.
5. Is this calculator suitable for quick exam preparation?
It is ideal for revising relationships among moles, molar mass, and particle counts. Try pairing it with practice problems and related tools such as mole-to-mass converters to strengthen intuition before quizzes or exams.