Chemistry & Science Calculator
Molar mass, solution concentration, dilution, gas laws, pH analysis, and a full scientific unit converter — everything a student or lab needs.
Select units and enter a value to convert
Type a chemical formula above — results appear instantly
Enter solute mass, volume, and molar mass to see all concentration units
Leave one field empty — it will be solved using C₁V₁ = C₂V₂
Fill in three of the four variables (P, V, n, T) to solve for the fourth
Select a mode, fill in values, and click Calculate pH
Advanced Unit Converter
Physics and chemistry units with automatic dimension validation. Prevents invalid conversions like kg → Kelvin.
Molar Mass Calculator
Parse any chemical formula including nested parentheses: Fe₂(SO₄)₃, Ca(OH)₂, complex organics.
Concentration Calculator
From mass and volume to Molarity, Molality, Normality, % w/v, % w/w, ppm — all at once.
Dilution Calculator
C₁V₁ = C₂V₂ — solve for any unknown. Includes step-by-step instructions.
Gas Law PV=nRT
Solve for P, V, n, or T with unit conversion built in. Supports atm, Pa, kPa, bar, torr.
pH Analyzer
Strong/weak acid and base pH, Henderson–Hasselbalch for buffers, Ka/Kb equilibria.
About the Chemistry Calculator Suite
This free online tool covers the most common calculations in general chemistry, analytical chemistry, and biochemistry lab courses. All calculations are performed in your browser — no data is sent to any server.
Molar Mass
Enter any chemical formula in standard notation. Nested parentheses (e.g. Fe2(SO4)3), polyatomic ions, and hydrates are all supported. The tool parses the formula into elements and multiplies each element's atomic mass by its count, then sums them.
Solution Concentration
Provide the solute mass (g), solution volume (mL), and molar mass (g/mol) to instantly obtain Molarity (mol/L), Molality (mol/kg), Normality (eq/L), mass percent (% w/w), volume percent (% w/v), and parts per million (ppm mg/L).
Dilution C₁V₁ = C₂V₂
The dilution equation states that the moles of solute are conserved. Enter any three of the four variables and the fourth is solved automatically. The results include step-by-step lab instructions.
Gas Laws PV = nRT
The ideal gas law relates pressure (P), volume (V), moles (n) and temperature (T) via the gas constant R = 0.08206 L·atm/mol·K. The calculator accepts multiple pressure and temperature units and converts internally.
pH Calculation
For strong acids, pH = −log[H⁺]. For weak acids, the tool solves the equilibrium Ka = x²/(C−x) for [H⁺]. Buffer pH is calculated using the Henderson–Hasselbalch equation: pH = pKa + log([A⁻]/[HA]).
Free Mole Calculator & Stoichiometry Helper
MoleMath helps you solve the mole problems that appear in every chemistry course: converting between grams, moles and particles, finding molar mass, and working through stoichiometry. Enter your values and see each step, so you learn the method instead of just getting an answer.
The mole is the chemist's counting unit: one mole contains 6.022 x 10^23 particles (Avogadro's number). Every calculation here builds on that idea plus the molar mass from the periodic table.
Grams to moles and back
Convert using molar mass with the steps shown.
Particles and Avogadro's number
Move between moles and atoms or molecules.
Stoichiometry
Use balanced equations and mole ratios to find reactants and products.
Study aid
Check your homework answers and understand each step.
How to use it
- Pick the calculation you need.
- Enter the substance or molar mass and the known quantity.
- Run the calculation.
- Review the worked steps.
Frequently asked questions
How do I convert grams to moles?
Divide the mass in grams by the molar mass in grams per mole.
What is Avogadro's number?
It is 6.022 x 10^23, the number of particles in one mole.
What is molar mass?
The mass of one mole of a substance, found by adding the atomic masses in its formula.
Is the mole calculator free?
Yes, it is free with no signup.