Stoichiometry
Molarity, molality, normality, Avogadro's number, and gas-phase molar mass are among the calculators handling the mole-based math that connects a balanced equation to real masses and concentrations, covering most problems that involve converting between grams, moles, and particles.
Calculators & Tools
Air-Fuel Ratio Calculator
Calculate the stoichiometric air-fuel ratio for any fuel from its chemical formula, convert to lambda (λ), and blend two fuels by volume to find the correct mixture target. Covers 13 presets including gasoline, diesel, ethanol, hydrogen, and methane — with a full six-step combustion derivation and a rich/lean gauge showing the three-way catalyst window.
Molecular Weight Calculator
Enter any chemical formula and get the molar mass in g/mol, a full elemental breakdown, and percent composition by mass — all calculated using IUPAC 2021 standard atomic weights. The step-by-step trace shows exactly how each element contributes to the total, so you can follow the working, not just read the answer. Handles parentheses, hydrates, nested groups, and coordination complexes.
Hydrogen Ion Concentration Calculator
The Hydrogen Ion Concentration Calculator converts between pH, [H⁺], pOH, and [OH⁻] using the water dissociation constant Kw at any temperature from 0 to 100 °C. It supports five modes including weak acid pH via the exact quadratic solution. All results include step-by-step working and a solution classification relative to the temperature-corrected neutral pH.
Normality Calculator
The Normality Calculator computes solution normality (N = equivalents/L) using mass, equivalent weight, and volume. It supports acid-base, redox, and precipitation reactions with built-in n-factors for 25 common reagents. Modes include: Find N from mass/volume, Find mass from target N/volume, N from molarity, molarity from N, and a titration solver using N₁V₁ = N₂V₂. Equivalent weight is calculated automatically from the selected reagent's molar mass and n-factor.
Atom Economy Calculator
Work out the atom economy of any reaction by entering the reactant and product formulas — molar masses are computed automatically using IUPAC 2021 atomic weights, no manual lookup needed. Compare two synthetic routes side by side to see which wastes fewer atoms, following Barry Trost's green chemistry framework and the EPA's 12 Principles.
Molarity Calculator
Calculate molarity from mass and volume, solve dilutions with C₁V₁ = C₂V₂, plan serial dilutions, or convert between M, mM, µM, ppm, and mg/mL — all in one tool with a dropdown of 20 common lab compounds for instant MW lookup. Every result comes with substituted step-by-step working so you can follow each conversion, not just trust the final number.
Avogadro's Number Calculator
Convert between moles, particle counts (atoms, molecules, formula units, or ions), and mass using Avogadro's number (6.02214076 × 10²³ mol⁻¹, exact 2019 SI value) — with support for SI prefixes from picomoles to kilomoles. Includes an atom drill-down showing individual element counts within a molecule, plus a Faraday tab for electrolysis charge-to-mass calculations.
Mole Calculator
Convert instantly between moles, grams, particle count, and gas volume at STP — enter any known value and the molar mass to get all five quantities at once. Step-by-step working is shown with your actual numbers substituted in, exactly as a chemistry teacher would write it on the board.
Mole Fraction Calculator
The Mole Fraction Calculator computes mole fractions (x_i = n_i / Σn) for mixtures of up to 6 components. Each component accepts moles directly or mass plus molar mass (auto-converts). It includes Dalton's Law partial pressure calculation (P_i = x_i × P_total) and an optional Raoult's Law vapour pressure panel (P_i = x_i × P°_i with total bubble-point pressure). Results are displayed in a table with the sum-of-fractions verification.
PPM to Molarity Calculator
The PPM to Molarity Calculator converts parts per million (ppm) to molarity (mol/L) and vice versa using M = ppm / (1000 × MM). It supports two ppm bases: mg/L (for dilute aqueous solutions) and mg/kg (mass fraction, with optional density correction). Outputs include molarity, mg/L, g/L, ppm, ppb, and %w/v. Includes 16 preset solutes and ions with correct molar masses, plus a custom entry option.
Grams to Moles Calculator
The Grams to Moles Calculator converts any mass in grams to moles (and back) using the molar mass of the substance. Enter a chemical formula and the calculator parses the molar mass automatically from IUPAC atomic weights. It supports four modes: grams to moles, moles to grams, grams to molecules, and molecules to grams, with step-by-step working shown for every calculation.
Molality Calculator
The Molality Calculator converts moles, solute mass, molarity, or mass percent into molality (mol/kg) with step-by-step working. It includes a colligative properties panel that calculates freezing point depression and boiling point elevation for six common solvents using van't Hoff factors for electrolyte solutions.
Molar Mass of Gas Calculator
The Molar Mass of Gas Calculator uses the ideal gas law (PV = nRT) to find the molar mass of any gas from its measured pressure, volume, temperature, and mass. It accepts pressure in atm, kPa, mmHg, or bar; volume in L, mL, or m³; and temperature in °C, K, or °F. It also solves for any other variable and includes a gas density mode and optional van der Waals real-gas correction for 9 common gases.