Chemistry Calculators
Chemistry is arithmetic with a very good memory for conventions, and the conventions are where the marks go. These calculators keep them: all 118 elements with their standard atomic weights, a formula parser that understands `Cu(NO3)2`, brackets and hydrates like `CaSO4·2H2O`, an equation balancer that solves the element-count matrix exactly rather than by trial and error, and a working line under every answer that shows the formula with your numbers already substituted.
Most popular
- chemistryMolar Mass● ready
Type a formula — nested groups and hydrates included — and get its molar mass in g/mol plus each element's contribution in grams and as a percentage.
- chemistryEquation Balancer● ready
Type an unbalanced equation and get the balanced one, with the atom count on each side checked element by element.
- chemistrypH & pOH● ready
Enter any one of pH, pOH, [H⁺] or [OH⁻] and get all four, with the solution labelled acidic, basic or neutral.
- chemistryIdeal Gas Law● ready
Enter any three of pressure, volume, amount and temperature and get the fourth — with the unit chosen per field and temperatures converted to kelvin internally.
- chemistryPercent Composition● ready
Enter a formula and get every element's share of the mass as a percentage — sorted largest first, and again in the order the formula was written.
Moles & Molar Mass
- chemistryMolar Mass● ready
Type a formula — nested groups and hydrates included — and get its molar mass in g/mol plus each element's contribution in grams and as a percentage.
- chemistryMoles● ready
Enter a mass with its molar mass, or a particle count on its own, and get the amount in moles — with the substituted formula underneath.
- chemistryGrams ↔ Moles● ready
One field and a direction: give a mass and get moles, or give moles and get the mass that many moles weighs, using the molar mass of your formula.
- chemistryMolecules ↔ Moles● ready
Enter a molecule count and get moles, or enter moles and get the count — with the answer echoed in scientific notation so the scale stays readable.
- chemistryPercent Composition● ready
Enter a formula and get every element's share of the mass as a percentage — sorted largest first, and again in the order the formula was written.
Solutions
- chemistryMolarity● ready
Get the concentration of a solution from a mass of solid or a number of moles and a volume — in mol/L, with mM shown too.
- chemistryMolality● ready
Divide moles of solute by kilograms of solvent — enter a weighed mass or a mole count, choose g or kg for the solvent, and get mol/kg with the working shown.
- chemistryNormality● ready
N = M × equivalents per mole — enter the molarity (or a weighed mass and volume) and the equivalents, with one-tap presets for HCl, H2SO4 and H3PO4.
- chemistryDilution● ready
Enter any three of the four dilution values and the fourth is solved for — how much stock, how much final volume, or what concentration you end up with.
- chemistryBeer-Lambert Law● ready
Enter any three of absorbance, molar absorptivity, path length and concentration; the fourth is solved for, with transmittance and millimolar concentration alongside.
Formulas & Equations
- chemistryEmpirical Formula● ready
Give each element's mass (or percentage) and get the empirical formula, with the moles and the ratio-to-smallest shown for every element.
- chemistryMolecular Formula● ready
Enter the empirical formula and the molar mass of the compound and get the multiplier n and the molecular formula it produces.
- chemistryEquation Balancer● ready
Type an unbalanced equation and get the balanced one, with the atom count on each side checked element by element.
- chemistryStoichiometry● ready
Enter a balanced equation, an amount of one species and the species you want, and get the moles and mass produced — with each step of the ratio shown.
- chemistryLimiting Reagent● ready
Give the starting moles of every reactant and get the limiting reagent, the excess left in each other reactant and the theoretical yield of each product.
- chemistryTheoretical Yield● ready
Balance the equation, find the limiting reagent, and get the product mass the reaction cannot beat — with every product listed and the working shown.
- chemistryPercent Yield● ready
Divide what you got by what the equation promised, in grams or moles — and if the answer tops 100%, the page says what that really means instead of capping it.
Measurement & Gas Laws
- chemistryAtomic Mass● ready
Find an element's atomic mass from the periodic table — or enter isotope masses and abundances and see the abundance-weighted average that produces the number the table prints.
- chemistrypH & pOH● ready
Enter any one of pH, pOH, [H⁺] or [OH⁻] and get all four, with the solution labelled acidic, basic or neutral.
- chemistryIdeal Gas Law● ready
Enter any three of pressure, volume, amount and temperature and get the fourth — with the unit chosen per field and temperatures converted to kelvin internally.
- chemistryGas Laws● ready
Pick the law that fits the problem, enter the values you know and leave one blank — Boyle, Charles, Gay-Lussac or the combined gas law.
All tools
- chemistryMolar Mass● ready
Type a formula — nested groups and hydrates included — and get its molar mass in g/mol plus each element's contribution in grams and as a percentage.
- chemistryMoles● ready
Enter a mass with its molar mass, or a particle count on its own, and get the amount in moles — with the substituted formula underneath.
- chemistryGrams ↔ Moles● ready
One field and a direction: give a mass and get moles, or give moles and get the mass that many moles weighs, using the molar mass of your formula.
- chemistryMolecules ↔ Moles● ready
Enter a molecule count and get moles, or enter moles and get the count — with the answer echoed in scientific notation so the scale stays readable.
- chemistryPercent Composition● ready
Enter a formula and get every element's share of the mass as a percentage — sorted largest first, and again in the order the formula was written.
- chemistryMolarity● ready
Get the concentration of a solution from a mass of solid or a number of moles and a volume — in mol/L, with mM shown too.
- chemistryDilution● ready
Enter any three of the four dilution values and the fourth is solved for — how much stock, how much final volume, or what concentration you end up with.
- chemistryBeer-Lambert Law● ready
Enter any three of absorbance, molar absorptivity, path length and concentration; the fourth is solved for, with transmittance and millimolar concentration alongside.
- chemistryEmpirical Formula● ready
Give each element's mass (or percentage) and get the empirical formula, with the moles and the ratio-to-smallest shown for every element.
- chemistryMolecular Formula● ready
Enter the empirical formula and the molar mass of the compound and get the multiplier n and the molecular formula it produces.
- chemistryEquation Balancer● ready
Type an unbalanced equation and get the balanced one, with the atom count on each side checked element by element.
- chemistryStoichiometry● ready
Enter a balanced equation, an amount of one species and the species you want, and get the moles and mass produced — with each step of the ratio shown.
- chemistryLimiting Reagent● ready
Give the starting moles of every reactant and get the limiting reagent, the excess left in each other reactant and the theoretical yield of each product.
- chemistrypH & pOH● ready
Enter any one of pH, pOH, [H⁺] or [OH⁻] and get all four, with the solution labelled acidic, basic or neutral.
- chemistryIdeal Gas Law● ready
Enter any three of pressure, volume, amount and temperature and get the fourth — with the unit chosen per field and temperatures converted to kelvin internally.
- chemistryGas Laws● ready
Pick the law that fits the problem, enter the values you know and leave one blank — Boyle, Charles, Gay-Lussac or the combined gas law.
- chemistryAtomic Mass● ready
Find an element's atomic mass from the periodic table — or enter isotope masses and abundances and see the abundance-weighted average that produces the number the table prints.
- chemistryMolality● ready
Divide moles of solute by kilograms of solvent — enter a weighed mass or a mole count, choose g or kg for the solvent, and get mol/kg with the working shown.
- chemistryNormality● ready
N = M × equivalents per mole — enter the molarity (or a weighed mass and volume) and the equivalents, with one-tap presets for HCl, H2SO4 and H3PO4.
- chemistryTheoretical Yield● ready
Balance the equation, find the limiting reagent, and get the product mass the reaction cannot beat — with every product listed and the working shown.
- chemistryPercent Yield● ready
Divide what you got by what the equation promised, in grams or moles — and if the answer tops 100%, the page says what that really means instead of capping it.
About Chemistry Calculators
Introductory chemistry is a small number of relationships — molar mass, the mole, concentration, the gas laws, pH — applied to a large number of compounds, and the difficulty is almost never the algebra. It is the bookkeeping: whether the volume is in litres, whether the temperature is absolute, whether the subscript was meant to be a 2 or a 3. These tools handle the bookkeeping so the chemistry stays in view. Every result is shown with its substituted formula rather than as a bare number, because a mole calculation nobody can follow is a mole calculation nobody should use.
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Convert units and work with numbers — length, weight, temperature, and more.
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- Physics Calculators
Kinematics, forces, energy, electricity, waves and fluids — with units per field and the working shown.
Frequently asked questions
What is a mole, in plain language?
It is a count, the way a dozen is a count: 6.022 × 10²³ particles. The number is not round because it was chosen to make something else come out round — one mole of carbon-12 weighs exactly 12 grams. That is what makes moles the bridge between a balance, which measures mass, and a reaction, which cares about how many particles react.
Why do I need the molar mass for so many calculations?
Because it converts between the two things you can measure and the thing the chemistry depends on. A balance gives you grams; a reaction is governed by moles. Dividing grams by molar mass gives moles, and multiplying back gives the mass you would actually weigh out. Almost every calculation in this category passes through it.
Do these tools handle hydrates and brackets?
Yes. Parentheses and square brackets both work and can nest, so `Cu(NO3)2` and `K4[Fe(CN)6]` parse correctly, and a hydrate written with a middle dot — `CaSO4·2H2O` — multiplies everything after the dot by the number in front of it. The formula field shows its own parse as you type, so a mis-typed subscript is visible before it reaches the arithmetic.
How does the equation balancer work?
It builds the element-count matrix and solves for its integer null space over exact big-integer fractions — a balanced equation is precisely a positive integer vector in that space. That means the coefficients are exact integers rather than something rounded, and two honest failure modes are reported instead of hidden: an equation with different elements on each side cannot be balanced at all, and one that is really two reactions (`C + O2 -> CO + CO2`) has a whole family of answers rather than one.
Are my formulas or values stored anywhere?
No. The periodic table is bundled with the page, everything is computed in the browser, and nothing typed here is uploaded or kept after a reload. The tools also keep working offline once the page has loaded.