Mole Calculator
Calculate moles, mass, particles, and solution concentration using standard chemistry formulas.
Avogadro's number used: 6.02214076 × 1023 particles/mol.
What this calculating moles calculator does
The mole is one of the most important concepts in chemistry because it connects the microscopic world (atoms and molecules) to measurements you can actually make in a lab (grams, liters, and concentrations). This calculator helps you quickly switch between those units using reliable formulas.
Whether you are working on stoichiometry homework, preparing solutions, or checking lab data, this tool reduces arithmetic errors and speeds up your workflow.
Core formulas for calculating moles
n = moles, m = mass (g), M = molar mass (g/mol)
n = moles, N = number of particles, NA = 6.02214076 × 1023
n = moles, C = molarity (mol/L), V = volume (L)
How to use the calculator
1) Select the conversion type
Use the dropdown at the top of the calculator to pick what you want to find: mass to moles, moles to mass, particles to moles, moles to particles, or concentration-based calculations.
2) Enter known values
- Type values using standard numbers or scientific notation (for example, 3.5e22).
- Use molar mass in g/mol (you can get this from the periodic table or a formula mass calculation).
- For solution problems, set volume units correctly (L or mL).
3) Click Calculate
The tool displays the formula used and the final answer with appropriate units. Use the Clear button to reset quickly.
Worked examples
Example A: grams to moles
Suppose you have 36.03 g of water (H2O). The molar mass of water is approximately 18.015 g/mol.
n = 36.03 / 18.015 = 2.00 mol
Example B: particles to moles
If you have 1.2044 × 1024 molecules of CO2, then:
n = (1.2044 × 1024) / (6.02214076 × 1023) ≈ 2.00 mol
Example C: moles to molarity
You dissolve 0.50 mol NaCl in 250 mL solution. Convert volume first: 250 mL = 0.250 L.
C = n / V = 0.50 / 0.250 = 2.0 mol/L
Common molar masses (quick reference)
| Substance | Formula | Molar Mass (g/mol) |
|---|---|---|
| Water | H2O | 18.015 |
| Carbon dioxide | CO2 | 44.009 |
| Sodium chloride | NaCl | 58.44 |
| Glucose | C6H12O6 | 180.16 |
| Oxygen gas | O2 | 31.998 |
Tips to avoid mistakes when calculating moles
- Always verify units before calculating.
- Use full molar mass precision until the final step, then round appropriately.
- Convert mL to L when using molarity formulas.
- Check if your result is chemically reasonable (very large or tiny values may signal a unit error).
FAQ
Why is the mole used in chemistry?
Chemical reactions happen between particles, but we measure substances by mass or volume. The mole links those two scales.
Can I use this for stoichiometry?
Yes. This calculator is especially useful for converting between measured data and moles, which is the first step in most stoichiometry problems.
Does this work for atoms, molecules, and ions?
Yes. The particles conversion mode uses Avogadro's constant and works for any counted chemical entities.
Final note
A good calculating moles calculator should be quick, clear, and trustworthy. Use this page as a practical helper for homework, exam review, and lab prep. If you are doing multi-step reaction problems, solve one conversion at a time and keep your units visible throughout.