Free Online Chemistry Calculators

Acid-Base & pH Chemistry Calculators cover the reactions and measurements at the heart of every acid-base unit. Calculate pH, pOH, and hydrogen ion concentration directly, or find the pH of a strong acid, strong base, weak acid, or weak base using the appropriate equilibrium approach. Work through an acid-base titration or full titration curve, find the equivalence point, or calculate Ka, Kb, and pKb for weak acid/base dissociation.

For buffer chemistry specifically, this section includes acetate buffer, phosphate buffer, and Tris buffer calculators, plus a general buffer preparation and buffer capacity calculator. There's also a neutralization calculator, polyprotic acid calculator, and isoelectric point calculator for amino acids and proteins.

Analytical Chemistry Calculators support the instrumentation and measurement techniques used to identify and quantify chemical samples. Interpret mass spectrometry and native mass spectrometry data, calculate NMR chemical shift and IR frequency, or build a calibration curve for a chromatography or HPLC method. Determine isotope distribution, GC retention index, and adiabatic flame temperature for combustion analysis.

This section also covers data quality and method validation: limit of detection, limit of quantification, standard deviation, and significant figures calculators, plus specialized tools like the arterial blood gas (ABG) calculator, crude fibre calculator, estimation of calcium calculator, and soluble protein calculator for clinical and food-science analysis.

Biochemistry Calculators bring molecular biology and enzyme kinetics formulas into one place for lab and coursework use. Calculate DNA/RNA molarity, Tm (melting temperature), annealing temperature, and OD260/OD280 ratio for nucleic acid work, or run an ELISA calculator and cell dilution calculator for assay prep. The Michaelis-Menten equation and enzyme activity calculators cover enzyme kinetics, while the amino acid calculator, calibration curve calculator, and resuspension calculator round out everyday biochemistry lab math.

Chemical Engineering Calculators cover the unit operations and process design math used in industrial and process chemistry. Design a CSTR, PFR, or batch reactor, size a distillation column or absorption tower, or run a flash calculation and Raoult's Law distillation calculator for vapor-liquid equilibrium. Balance mass and energy across a process with the mass balance and energy balance calculators.

This section also includes equipment sizing tools: heat exchanger, pump sizing, and pipe flow (chemistry) calculators, plus particle settling velocity, filtration rate, residence time distribution, and the Antoine equation calculator for vapor pressure estimation.

Chemical Equations & Reactions Calculators help you balance and predict the outcome of chemical reactions. Use the chemical equation balancer to balance any equation, or the balancing redox reactions calculator specifically for oxidation-reduction chemistry. Predict reaction type and products with the single displacement, double displacement, and precipitation reaction predictor calculators, and check reactivity order with the activity series calculator.

This section also covers combustion chemistry with the combustion analysis and combustion reaction calculators, a net ionic equation calculator for aqueous reactions, and a solubility rules calculator for predicting whether a precipitate forms.

Chemical Equilibrium Calculators help you work through equilibrium constants and reaction direction. Calculate the equilibrium constant (Kc & Kp), Kp specifically, or Ksp for solubility product problems, and use an ICE-table calculator to organize initial, change, and equilibrium concentrations. The reaction quotient (Q) calculator tells you which direction a reaction will shift, Le Chatelier's principle calculator predicts the effect of a stress on equilibrium, and the rate constant calculator connects equilibrium to reaction kinetics.

Chemical Kinetics Calculators cover how fast a reaction proceeds and what controls that speed. Calculate reaction rate and rate law directly from experimental data, or work through zero-order, first-order, and second-order reaction calculators to find the right rate equation for your data. The half-life (chemical) calculator estimates how long a reactant takes to deplete, while the collision theory calculator connects molecular collisions to reaction rate.

Chemical Thermodynamics Calculators cover the heat and energy changes that accompany chemical reactions. Calculate enthalpy using Hess's Law, heat of reaction, heat of formation, and heat of combustion, or work through a bomb calorimeter, coffee cup calorimeter, or general calorimetry calculator to find experimental heat values. The specific heat and heat capacity (chemistry) calculators relate temperature change to energy absorbed or released.

This section also includes the Gibbs phase rule calculator for phase equilibria, plus STP calculator and STP gas volume converter for standard temperature and pressure conditions.

Chemistry Unit Conversion Calculators handle the constant unit-switching that comes with lab work and coursework. Use the all-in-one chemistry unit converter for quick conversions, or dedicated tools for mass, volume, pressure, temperature, energy, and density-volume conversions. The concentration unit converter switches between molarity, molality, and percent concentration, while the wavelength frequency energy converter relates spectroscopy units to each other.

Colligative Properties Calculators cover how solutes change the physical properties of a solvent. Use the colligative properties calculator for a general boiling point elevation or freezing point depression problem, or calculate osmotic pressure and vapor pressure directly. The vapor pressure of water calculator gives quick reference values at any temperature, Raoult's Law calculator relates vapor pressure to solution composition, and the boiling point at altitude calculator adjusts for changing atmospheric pressure.

Electrochemistry Calculators cover the reactions and measurements behind batteries, electrolysis, and redox chemistry. Calculate cell EMF, standard electrode potential, and run a full galvanic cell or electrolytic cell calculation, or convert Coulombs to Faraday for charge-based stoichiometry. The ionic strength, activity coefficient, and equivalent conductivity calculators support solution-phase electrochemistry, while the electrolysis calculator estimates the products of passing current through a solution.

Environmental & Water Chemistry Calculators cover the water quality and treatment chemistry used in environmental science and water treatment plants. Calculate alkalinity, biological oxygen demand (BOD), and chemical oxygen demand (COD) to assess water quality, or use the Langelier saturation index and Ryznar stability index calculators to predict scaling or corrosion in water systems. Dosing tools include the chlorine dosage and fluoride dosing calculators for water treatment.

This section also includes a pH adjustment calculator, sludge volume index calculator for wastewater treatment, and a rainfall volume calculator for stormwater and environmental assessments.

Gas Laws Calculators cover the classic relationships between pressure, volume, temperature, and moles of gas. Calculate partial pressure directly or use Dalton's Law of partial pressures for gas mixtures, and estimate rate of effusion with Graham's Law calculator. The Van't Hoff factor calculator adjusts colligative property calculations for ionic solutes that dissociate in solution.

General & Atomic Chemistry Calculators cover the foundational concepts every chemistry course starts with. Calculate molar mass, atomic mass, and average atomic mass, or work out empirical formula, molecular formula, and percent composition from experimental data. Look up electron configuration, atomic number, electronegativity, and oxidation number, or use the periodic table tool as a quick reference.

For bonding and solid-state chemistry, this section also covers bond order, lattice energy, Born-Haber cycle, effective nuclear charge, and percent ionic character calculators, plus crystallography tools like Miller indices, interplanar spacing, cubic cell, and lattice parameter calculators. There are also chemical formula, chemical name, ion, ion/atom counter, and isotope calculators for everyday nomenclature and composition problems.

Nuclear Chemistry Calculators cover radioactive decay and nuclear stability calculations. Estimate nuclear half-life and model a full nuclear decay chain, or calculate beta decay and binding energy per nucleon for a given isotope. The neutron activation calculator estimates radioactivity induced by neutron bombardment, and the radioactive decay (nuclear) calculator finds remaining quantity or activity after a given time.

Organic Chemistry Calculators cover the structure, naming, and reactivity calculations that come up throughout an organic chemistry course. Name a compound with the IUPAC naming calculator, determine hybridization, and work out degree of unsaturation or double bond equivalent from a molecular formula. The R/S & E/Z configuration calculator assigns stereochemistry, the isomer counter calculator counts possible structural isomers, and the organic reaction predictor estimates likely products.

For lipid and polymer chemistry, this section also includes acid value, iodine value, peroxide value, hydroxyl value, saponification number, and free fatty acid calculators, plus enantiomeric excess (ee), degree of polymerization, crude protein, chemical oxygen demand, and liquid ethylene density calculators.

Physical Chemistry Calculators cover the equations connecting chemical concentration, kinetics, and molecular behavior. Calculate molarity, molality, and mole directly, or work through the Arrhenius equation and activation energy calculator for temperature-dependent reaction rates. The Nernst equation, Henry's Law, and Langmuir isotherm calculators cover electrochemistry, gas solubility, and surface adsorption, while diffusion coefficient and viscosity (chemistry) calculators describe molecular transport.

This section also supports lab and clinical chemistry: molecular weight, protein molecular weight, DNA concentration, buffer pH, solution dilution, and theoretical yield calculators, plus specialized tools like FRET efficiency, BET surface area, Randles-Sevcik equation, Young-Laplace equation, radiocarbon dating, and half-life (radioactive) calculators.

Reference & Tools Calculators cover a handful of quick-lookup chemistry calculations that don't fit neatly elsewhere. Use the Bohr model energy level calculator to find electron energy transitions, calculate wavelength or frequency (chemistry) for a given photon, and look up polyatomic ion formulas and charges with the polyatomic ion calculator.

Solutions & Concentrations Calculators cover every way chemists express how much solute is dissolved in a solution. Calculate concentration, mass percent, mole fraction, and molar volume, or convert between mass concentration and molar concentration, percentage concentration and molarity, or PPM and molarity. The alligation calculator and mixing ratio calculator solve two-component mixture problems, while the two-component mixture solver generalizes the same logic.

This section also includes a molar mass of gas calculator, water hardness calculator, TDS (total dissolved solids) calculator for water testing, and a saponification value calculator for fats and oils.

Stoichiometry Calculators cover the mole-based math that connects chemical equations to real quantities. Convert grams to moles, mass to moles, moles to grams, moles to atoms, and moles to particles, or calculate mole fraction and molar ratio between reactants and products. The stoichiometry calculator ties everything together for a full reaction calculation, while actual yield, theoretical yield, and percent yield calculators evaluate how efficient a reaction actually was.

This section also includes an atom economy calculator for green chemistry, Avogadro's number calculator, air-fuel ratio (AFR) calculator for combustion stoichiometry, mixture average molar mass calculator, and a u to grams converter for atomic mass units.