Chemistry Calculators
Fast, unit-aware calculators for the laws chemists use every day, from preparing solutions to predicting reaction rates and cell potentials.
Ideal Gas Law Calculator
PV = nRT
Combined Gas Law Calculator
P₁V₁/T₁ = P₂V₂/T₂ (Boyle's, Charles's & Gay-Lussac's laws)
Molarity Calculator
Concentration from mass, molar mass and volume
Dilution Calculator (C₁V₁ = C₂V₂)
Stock solution dilution
pH Calculator
pH, pOH, [H⁺] and [OH⁻] at 25 °C
Half-Life & Radioactive Decay Calculator
N = N₀·(½)^(t/t½)
Arrhenius Equation Calculator
Reaction rate constant vs temperature
Nernst Equation Calculator
Cell potential under non-standard conditions
Osmotic Pressure Calculator (van 't Hoff)
π = iMRT
Beer–Lambert Law Calculator
Absorbance A = ε·l·c
Henry's Law Calculator
Gas solubility C = k_H·P
Chemistry laws covered
These calculators cover the core quantitative laws of general and physical chemistry:
- Gas laws — the ideal gas law PV = nRT and the combined gas law, which includes Boyle's, Charles's and Gay-Lussac's laws.
- Solutions — molarity, dilution (C₁V₁ = C₂V₂), osmotic pressure and Henry's law for gas solubility.
- Acids and bases — the pH calculator, with pOH, [H⁺] and [OH⁻].
- Kinetics — the Arrhenius equation and half-life and first-order decay.
- Electrochemistry — the Nernst equation.
- Spectroscopy — the Beer–Lambert law.
Every calculator converts units automatically (°C → K, kPa → Pa, mL → m³ and so on), so you avoid the most common source of chemistry mistakes.
Chemistry laws at a glance
The key equations behind every chemistry calculator.
Ideal Gas Law
For an ideal gas, the product of pressure and volume equals the amount of gas times the gas constant times the absolute temperature. (Émile Clapeyron, 1834)
Open the Ideal Gas Law calculator →Combined Gas Law
For a fixed amount of gas, PV/T is constant. Holding T constant gives Boyle's law, holding P constant gives Charles's law, and holding V constant gives Gay-Lussac's law.
Open the Combined Gas Law calculator →Molar Concentration
Molarity is the amount of solute in moles per litre of solution.
Open the Molarity calculator →Dilution Equation
Diluting a solution does not change the amount of solute: the concentration times the volume is the same before and after.
Open the Dilution calculator →pH Definition (Sørensen)
pH is the negative base-10 logarithm of the hydrogen-ion activity, approximately −log₁₀[H⁺] in dilute solutions. (S. P. L. Sørensen, 1909)
Open the pH calculator →Law of Radioactive Decay
The number of undecayed nuclei decreases exponentially with time; in each half-life, half of what remains decays. (Ernest Rutherford & Frederick Soddy, 1902)
Open the Half-Life & Radioactive Decay calculator →Arrhenius Equation
The rate constant of a chemical reaction increases exponentially with temperature, governed by the activation energy. (Svante Arrhenius, 1889)
Open the Arrhenius Equation calculator →Nernst Equation
The potential of an electrochemical cell depends on the standard potential, the temperature, and the ratio of product to reactant activities. (Walther Nernst, 1889)
Open the Nernst Equation calculator →van 't Hoff Law of Osmotic Pressure
The osmotic pressure of a dilute solution equals the pressure the solute particles would exert as an ideal gas occupying the same volume. (Jacobus van 't Hoff, 1887)
Open the Osmotic Pressure calculator →Beer–Lambert Law
The absorbance of light by a solution is proportional to the concentration of the absorbing species and the path length. (Bouguer 1729, Lambert 1760, Beer 1852)
Open the Beer–Lambert Law calculator →Henry's Law
At constant temperature, the amount of a gas that dissolves in a liquid is proportional to its partial pressure above the liquid. (William Henry, 1803)
Open the Henry's Law calculator →