Chemistry Tools & Calculators

Free browser-based calculators for solution preparation, reaction stoichiometry, acid-base chemistry, and substance data. Everything runs locally — your data is never uploaded.

Solution Preparation

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Make stock and working solutions: molarity, dilution, percent solutions and concentration conversions.

Molarity & Solution Preparation Calculator

Solve for molarity, solute mass, or solution volume from the other two values.

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Dilution Calculator

Calculate dilution using the C1V1 = C2V2 formula. Solve for any variable.

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Percent Solution Calculator

Calculate percent concentration (w/w, w/v, v/v) of a solution.

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Serial Dilution Calculator

Calculate concentration at each step of a serial dilution. Supports dilution factor and step count, with optional per-step volume.

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Concentration Converter

Convert between mg/mL and mM (molar concentration) using molar mass.

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Solubility Converter

Convert solubility units between g/L, mg/mL, mol/L, ppm and more, with mass-to-molar conversion by molecular weight.

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Solution Preparation Calculator

Calculate the mass of solid to weigh, or the stock volume and diluent needed, to prepare a solution of a target concentration and volume.

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Reactions & Stoichiometry

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Balance equations, predict products, and scale reactants to product amounts.

Reaction Product Predictor

Enter reactant names to look up compounds via PubChem and predict products of common reactions (combustion, acid-base) with a balanced equation.

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Chemical Equation Balancer

Balance a chemical equation automatically. Find stoichiometric coefficients (e.g. H2 + O2 -> H2O).

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Stoichiometry Calculator

Calculate reactant and product moles and masses from a balanced chemical equation — enter coefficients and formulas, then specify one known mass.

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Empirical Formula Calculator

Determine the empirical formula of a compound from elemental mass percentages. Converts each element to moles and simplifies to the smallest whole-number ratio.

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Molecular Formula Calculator

Determine the molecular formula from an empirical formula and molar mass. Calculates the integer multiplier and the full molecular formula.

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Titration Curve Calculator

Simulate strong- and weak-acid titrations with a strong base — plot the pH curve and find the equivalence point.

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Equilibrium / ICE Table Calculator

Solve reversible reaction equilibria with an ICE table and reaction extent from K, plus solubility and Ksp with the common-ion effect.

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Thermochemistry Calculator

Calculate heat from calorimetry, reaction enthalpy with Hess's law, and Gibbs free energy with the equilibrium constant.

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Electrochemistry Calculator

Apply the Nernst equation to a cell potential and use Faraday's laws to convert current and time into deposited mass.

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Chemical Kinetics Calculator

Use the Arrhenius equation for rate constants and activation energy, and calculate reaction rate and half-life from the rate law.

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Acids, Bases & Buffers

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pH, pKa and Henderson–Hasselbalch buffer calculations for biological systems.

pH Calculator

Calculate pH from [H⁺], or from pKa for weak acids and buffers (Henderson-Hasselbalch).

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pKa / Henderson-Hasselbalch

Solve the Henderson-Hasselbalch equation for pH, pKa or the conjugate base/acid ratio.

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Buffer Calculator

Design a buffer solution using the Henderson-Hasselbalch equation. Compute the [A⁻]/[HA] ratio, concentrations, moles, and masses.

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Polyprotic Acid pH Calculator

Calculate the pH and species distribution of a polyprotic acid (phosphoric, citric, EDTA, amino acids) from its pKa values, with a titration curve.

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Buffer Recipe Calculator

Scale PBS, TAE, TBS, TE, SSC, HEPES and Tris stock recipes to any final volume, for 1× working solution or undiluted stock.

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Structure & Composition

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Parse formulas, compute molar mass and elemental composition, browse the periodic table.

Molar Mass Calculator

Calculate the molar mass of a compound from its chemical formula (e.g. H2O, NaCl).

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Formula Parser

Parse a chemical formula and view element composition, atom counts, and mass contributions.

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SMILES to Molecular Weight

Enter a SMILES string to get the molecular formula and molar mass, with implicit hydrogen handling.

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Interactive Periodic Table

Browse all 118 elements. Click for atomic weight, electron shells, density, melting & boiling point, and electronegativity. Temperature slider & property heatmap.

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Density Calculator

Calculate density (ρ = m/V), mass, or volume from the other two values. Supports any combination of known and unknown variables.

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MS Isotope Distribution Calculator

Compute the isotope pattern, monoisotopic and average mass of a formula for mass spectrometry, including M+1 and M+2 peaks for C, Cl, Br and S.

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Molecular Geometry Calculator

Predict VSEPR molecular geometry, hybridization, bond angles and polarity from bonded atoms and lone pairs, and calculate formal charge.

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Lab Conversions

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Everyday bench conversions: metric units, centrifuge RPM to g-force and back.

Unit Converter

Convert between metric units for mass (g, mg, μg, ng), volume (L, mL, μL), and concentration (M, mM, μM, nM).

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Centrifuge RPM ↔ RCF Converter

Convert between centrifuge RPM and relative centrifugal force (RCF, × g) using the rotor radius.

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Beer-Lambert Law

Solve A = ε · c · l for whichever quantity is missing, convert to transmittance, and find how far to dilute into range.

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Gas Laws Calculator

Solve the ideal gas equation for pressure, volume, moles or temperature, and compute colligative properties including boiling point, freezing point and osmotic pressure.

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