Science & Chemistry Calculators — United Kingdom
The lab and classroom sums — solutions, moles, acids, gases, rates, heredity, measurement — with the working shown.
Solutions & concentration
Molarity Calculator
Find the molarity of a solution from the mass of solute, its molar mass and the solution volume — with moles, g/L and millimolar alongside.
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Dilution Calculator
Work out how much stock solution to dilute to make a given volume at a lower concentration — C₁V₁ = C₂V₂ — with the diluent volume and dilution factor.
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Solution Preparation Calculator
How many grams of a compound to weigh out to make a solution of a given molarity and volume — the reverse of the molarity calculation.
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Percent Solution Calculator
Calculate a percent concentration — weight/volume, weight/weight or volume/volume — from the amounts, or the amount needed for a target percentage.
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PPM Calculator
Convert parts per million to milligrams per litre, percent, parts per billion and mg/kg — or calculate ppm from a mass in a mass or volume.
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Boiling Point Elevation Calculator
Find how much a dissolved substance raises the boiling point and lowers the freezing point of water — ΔT = i × K × m — from the molality and the van't Hoff factor.
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Concentration Calculator
Convert between molarity, mass concentration, percent and ppm — the four ways the same solution gets labelled.
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PPM to Molarity Calculator
Convert parts per million to molarity and back — the conversion behind every water-quality and trace-analysis result.
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Dilution Factor Calculator
The dilution factor from the volumes, and the concentration it produces — with the notation pinned down, since 1:10 means two different things.
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Serial Dilution Calculator
The concentration at every step of a serial dilution — with the total dilution reached and the volumes for each tube.
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Solution Dilution Calculator
The dilution equation solved for whichever variable you need — stock volume, final volume, or either concentration.
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Mass Concentration to Molar Concentration Calculator
Convert mass concentration to molar concentration and back, using the molar mass — with the mass needed to make a given volume.
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Percentage Concentration to Molarity Calculator
Convert a percentage concentration to molarity — for weight/volume, weight/weight or volume/volume, including concentrated acids.
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Bleach Dilution Calculator
How much bleach to add for a target chlorine concentration — for sanitising, disinfecting or water treatment.
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Mixing Ratio Calculator
The amounts for a two-part mix at a given ratio — resin and hardener, fuel and oil, concentrate and water.
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Molality Calculator
Molality from mass or moles of solute and the solvent mass — the concentration unit that does not change with temperature.
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Mole Fraction Calculator
The mole fraction of each component in a two-part mixture — from masses or moles, with the mass fraction alongside.
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Freezing Point Depression Calculator
The freezing point of a solution — the depression a dissolved solute causes, and how much you need for a target temperature.
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Osmotic Pressure Calculator
The osmotic pressure of a solution — the pressure needed to stop water flowing across a membrane into it.
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Normality Calculator
Normality from molarity and equivalents — the concentration unit titrations still use, and how it relates to molarity.
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Solubility Product Calculator
Solubility product from molar solubility and back — for any salt stoichiometry, with the common-ion effect.
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Ionic Strength Calculator
The ionic strength of a solution from the concentration and charge of each ion — the quantity activity coefficients and Debye lengths depend on.
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Moles, mass & reactions
Molar Mass Calculator
Type a chemical formula — H2O, NaCl, C6H12O6, Ca(OH)2, CuSO4·5H2O — and get its molar mass with the element breakdown.
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Moles to Grams Calculator
Convert between moles and grams of a substance using its molar mass — either direction.
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Atoms to Moles Calculator
Convert a number of atoms, molecules or ions to moles and back using the Avogadro constant, 6.022 × 10²³ per mole.
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Percent Yield Calculator
Calculate the percent yield of a reaction from the actual mass obtained and the theoretical maximum, with the loss.
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Titration Calculator
Calculate the concentration of an acid (or base) from a titration — titrant volume and molarity, sample volume and the mole ratio of the neutralisation.
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Molar Ratio Calculator
The molar ratio between two reactants, which one runs out first, and how much product the reaction can make.
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Air-Fuel Ratio Calculator
Air-fuel ratio, lambda and equivalence ratio for any fuel — with the stoichiometric point and whether the mixture is rich or lean.
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Combustion Reaction Calculator
The oxygen and air a hydrocarbon needs to burn, and the carbon dioxide and water it produces — from the formula CₓHᵧ.
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Percent Composition Calculator
The mass percentage of each element in a compound — from its formula, with the mass of each element in a given sample.
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Empirical Formula Calculator
The empirical formula from percent composition — and the molecular formula if you know the molar mass.
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Atom Economy Calculator
Atom economy — the share of reactant mass that ends up in the desired product — and how it differs from percent yield.
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Average Atomic Mass Calculator
The average atomic mass of an element from the masses and natural abundances of up to four isotopes — the number printed on the periodic table.
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Degree of Unsaturation Calculator
The degree of unsaturation — how many rings and double bonds a molecular formula must contain — from its atom counts.
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Acids, buffers & gases
pH Calculator
Convert between pH, pOH, hydrogen-ion and hydroxide-ion concentration — enter any one and get the other three.
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Buffer pH Calculator
Calculate the pH of a buffer from the pK_a of the weak acid and the concentrations of its conjugate base and acid — the Henderson–Hasselbalch equation.
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Combined Gas Law Calculator
Find the new volume of a gas when its pressure and temperature change — the combined gas law, which contains Boyle's, Charles's and Gay-Lussac's laws.
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Reaction Quotient Calculator
The reaction quotient Q from current concentrations, compared against K to tell you which direction the reaction will run.
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Hydrogen Ion Concentration Calculator
Hydrogen ion concentration from pH, and pH from concentration — with pOH, hydroxide concentration and how far it sits from neutral.
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Molar Mass of a Gas Calculator
The molar mass of a gas from its mass, volume, pressure and temperature — the ideal gas law rearranged.
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Raoult's Law Calculator
The vapour pressure of a solution from the mole fraction of solvent — and the lowering a dissolved solute causes.
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Partial Pressure Calculator
The partial pressure of a gas in a mixture — from its mole fraction and the total pressure, or from moles, volume and temperature.
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Vapour Pressure Calculator
How a liquid's vapour pressure changes with temperature — the Clausius-Clapeyron equation, and the boiling point at any pressure.
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Henry's Law Calculator
How much gas dissolves in a liquid at a given partial pressure — Henry's law, behind carbonation, diving and dissolved oxygen.
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Equilibrium Constant Calculator
The equilibrium constant from equilibrium concentrations — with the Kc to Kp conversion and the free energy it implies.
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Rates, heat & light
Half-Life Calculator
How much of a radioactive isotope, drug or first-order reactant remains after a time, from its half-life — with the decay constant and the number of half-lives elapsed.
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Carbon Dating Calculator
Estimate the age of a sample from the percentage of carbon-14 remaining, using the 5,730-year half-life — and the reverse, the fraction left after a given age.
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Calorimetry Calculator
Find the heat absorbed by the water in a calorimeter — q = m c ΔT — and the enthalpy change per mole of the reactant, from a temperature rise.
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Beer–Lambert Law Calculator
Find a solution's concentration from its absorbance, the molar absorptivity and the path length — A = εlc — or the absorbance a concentration will give.
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Graham's Law Calculator
The relative rates at which two gases effuse or diffuse — lighter gases move faster, by the square root of the mass ratio.
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Rate Constant Calculator
The rate constant for a zero, first or second order reaction — from concentrations and time, or from the half-life.
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Activation Energy Calculator
Activation energy from two rate constants at two temperatures — or the rate change a temperature shift will cause.
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Gibbs Free Energy Calculator
Gibbs free energy from enthalpy and entropy — whether a reaction is spontaneous, and the temperature at which that changes.
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Lattice Energy Calculator
The lattice energy of an ionic compound — the energy holding the crystal together — by the Born-Landé equation.
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Nernst Equation Calculator
The cell potential away from standard conditions — the Nernst equation, for electrochemistry, pH electrodes and membrane potentials.
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Electrolysis Calculator
The mass deposited or gas evolved in electrolysis — from current, time and the number of electrons per ion.
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Enthalpy of Reaction Calculator
The enthalpy change of a reaction from the standard formation enthalpies of its products and reactants.
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Bond Energy Calculator
The approximate enthalpy of a reaction from the bonds broken and formed — the estimate you can make without a data table of formation enthalpies.
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Entropy Change Calculator
The entropy change of a reaction, a temperature change or a phase transition — the disorder term in every spontaneity calculation.
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Arrhenius Equation Calculator
The rate constant of a reaction at a given temperature from its activation energy and pre-exponential factor — and how much faster it goes at a second temperature.
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Biology & astronomy basics
Punnett Square Calculator
Cross two parents for a single gene and get the genotype and phenotype ratios of the offspring — a Punnett square worked out.
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Bacterial Growth Calculator
Work out how many cells a culture reaches after a given time from its doubling time — exponential growth — and how many generations that is.
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Hardy–Weinberg Calculator
From the share of a population showing a recessive trait, estimate the recessive and dominant allele frequencies and the carrier (heterozygote) frequency — p² + 2pq + q² = 1.
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Light Travel Time Calculator
How long light takes to travel a distance — kilometres, astronomical units or light-years — from the Moon to the nearest star.
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Weight on Other Planets Calculator
See what you would weigh on the Moon, Mars, Jupiter and the other bodies of the Solar System — mass stays the same, gravity does not.
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Measurement
Significant Figures Calculator
Round any number to a chosen number of significant figures, count the significant figures it already has, and see it in scientific notation.
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Percent Uncertainty Calculator
Convert an absolute uncertainty on a measurement to a percentage and back, and combine the uncertainties of two measurements that are multiplied or divided.
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Detention Time Calculator
How long water stays in a tank — hydraulic retention time — from the tank volume and the flow through it.
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Water Hardness Calculator
Water hardness converted between every scale — ppm as CaCO₃, grains per gallon, German, French and English degrees.
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Boiling Point at Altitude Calculator
The temperature water boils at for a given elevation — lower air pressure, lower boiling point, longer cooking.
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About these calculators
Each calculator applies one standard equation exactly as it appears in a chemistry or biology text, shows every substitution, and uses IUPAC atomic masses and CODATA constants.