Free Chemistry Calculators and STEM Tools for Students

pH Calculator

Calculate pH, pOH, hydrogen ion concentration [H⁺] and hydroxide ion concentration [OH⁻] for strong acids, weak acids, strong bases, weak bases, and buffer solutions.

Visualize pH on a display, and compute from acid or base concentrations. Includes calculators with Ka and Kb values for weak acids, and Henderson-Hasselbalch calculations for buffer solutions.

Limiting Reagent Calculator

Determine the limiting reagent, excess reagent, and theoretical yield for any chemical reaction.

Enter your reactants, their molar masses, and available quantities to instantly find which reagent runs out first and how much product can be formed. Useful for stoichiometry, lab planning, and yield calculations across all areas of synthesis.

Periodic Table

An interactive periodic table of elements with detailed data for all 118 elements.

Includes atomic number, atomic mass, electron configuration, electronegativity, melting and boiling points, phase at STP and elemental category.

Ideal for anyone studying atomic structure or elemental properties.

Molarity & Dilution Calculator

Calculate solution concentrations in mol/L and solve dilution equations using C₁V₁ = C₂V₂, across all common concentration units.

Perfect for preparing solutions in analytical chemistry, biochemistry, and general laboratory work, where instant concentration calculations are needed.

Chemistry Formula Sheet

A comprehensive, searchable formula reference covering thermodynamics, kinetics, electrochemistry, materials science, gases, and more.

Each formula is expandable, and many link to related tools, allowing one to test the relationships the equation defines.

Designed for chemistry students and scientists as a central reference tool for chemistry equations.

Gibbs Free Energy Calculator

Solve for Gibbs free energy change ΔG, enthalpy change ΔH, temperature or entropy change ΔS using the fundamental thermodynamic relation ΔG = ΔH − TΔS.

Instantly determine whether a reaction is spontaneous, non-spontaneous, or at equilibrium. Essential for physical chemistry, biochemistry, and chemical engineering thermodynamics problems.

Arrhenius Calculator

Solve the Arrhenius equation for rate constant k, activation energy Ea, or pre-exponential factor A.

Compare reaction rates at two different temperatures and explore how temperature dependence affects reaction kinetics.

Used widely in physical chemistry, chemical engineering, and materials science to model temperature-dependent rate behaviour.

Nernst Equation Calculator

Calculate electrochemical cell potential under non-standard conditions using the Nernst equation.

Solve for cell potential E, standard potential E°, reaction quotient Q, or number of electrons transferred. Interconvert equilibrium constant K and standard cell potential E°.

Ideal for electrochemists and battery or corrosion analysis.

Ideal Gas Law Calculator

Solve PV = nRT for any unknown, pressure, volume, moles, or temperature, with flexible unit selection across Pa, atm, bar, mmHg, L, m³, K, °C and much more.

Ideal for general chemistry, physical chemistry, and engineering thermodynamics problems involving gases under ideal conditions.

Titration Curve Visualizer

Plot and analyze titration curves for strong acid–strong base, weak acid–strong base, strong base–strong acid, and weak base-strong acid titrations.

Automatically calculates and marks the equivalence point, and provides a graph showing pH against volume of titrant added.

An essential tool for analytical chemistry and anyone studying volumetric analysis and acid-base equilibria.

Rate Law Calculator

Solve integrated rate law equations for 0th, 1st, and 2nd order reactions.

Calculate reactant concentration at any time, find the rate constant k from experimental data, or determine the time required to reach a given concentration.

Includes a reference table with all important formulae for each of the reaction orders.

Half-Life Calculator

Calculate radioactive decay parameters including half-life, remaining quantity, time elapsed or initial quantity of a radioisotope.

Supports all radioactive isotope, with a dropdown selection of the most common, and any time and mass units.

Useful for nuclear chemistry, radiometric dating, medical physics, and radiation safety calculations.

Empirical Formula Calculator

Determine the empirical formula and molecular formula of a compound from elemental percentage composition or raw mass data.

Enter the percentage of each element present and the tool reduces the ratios to the simplest whole-number formula. Also supports molecular formula determinations when provided with molar masses.

Beer-Lambert Calculator

Solve the Beer-Lambert law (A = εlc) for absorbance, molar absorptivity, concentration, or path length in UV-Vis spectroscopy.

Visualize the amount of light passing through a sample, and interconvert absorbance, transmittance and % transmittance.

Used in analytical chemistry, biochemistry, and materials science for spectrophotometric analyses.

Crystal Structure Viewer

Visualize and interact with 3D models of common crystal structures including body-centred cubic (BCC), face-centred cubic (FCC), simple cubic, diamond cubic, hexagonal close-packed (HCP), and more.

Rotate, zoom, and explore atomic packing arrangements.

Ideal for materials scientists, solid-state chemists, and condensed matter physicists.

Metal Complex Builder

Build coordination complexes interactively by selecting a transition metal, oxidation state, geometry, and ligands.

Automatically generates the IUPAC name and draws the crystal field d-orbital splitting diagram for octahedral, tetrahedral, and square planar geometries.

Essential for inorganic chemists studying coordination compounds and crystal field theory.

Raoult's Law Calculator

Calculate the vapour pressure of ideal liquid mixtures using Raoult's Law, and solve for boiling point elevation and freezing point depression using colligative property equations.

Enter component mole fractions and pure vapour pressures to find total and partial pressures.

Widely used in physical chemistry and chemical engineering for mixture and solution thermodynamics.

Thermodynamic Data Table

Access standard enthalpy of formation ΔHf°, Gibbs free energy of formation ΔGf°, and standard molar entropy S° data for over 100 common chemical substances.

Searchable and filterable by category, with information about compound formulae, names and phases

An essential reference tool for thermodynamics problems and Hess' Law calculations.

Molality Calculator

Calculate molality (mol/kg) of a solution from solute moles or mass, and solvent mass.

Molality is independent of temperature, making it the preferred concentration unit for colligative property calculations including boiling point elevation, freezing point depression, and osmotic pressure. Supports flexible input units for mass values.

Concentration Converter

Instantly interconvert between molarity (mol/L), mass percent (% w/w and % w/v), ppm, ppb, mg/dL, g/L, and more.

Enter a concentration in any unit and get the equivalent values across all common units simultaneously.

Useful for analytical chemistry, clinical biochemistry, environmental science, and laboratory work.

Spectrochemical Series

Explore the spectrochemical series of ligands ranked by crystal field splitting strength, from weak-field ligands like I⁻ to strong-field ligands like CN⁻.

Click any ligand to view its IUPAC name, charge, denticity, donor type, relative field strength and more.

An interactive reference for inorganic chemists and anyone studying crystal field theory, d-orbital splitting, and coordination complexes.