Chemistry calculators
Solutions, stoichiometry, gas laws and reaction calculations.
87 published calculatorsMixtures And Solutions 21
Activity Coefficient Calculator Activity coefficient calculator using Debye-Huckel or Davies equation. Supports single-ion and mean ionic modes, temperature adjustment, and three model comparisons.
Open Alligation Calculator: Mix Ratio and Volume Solver Calculate the alligation ratio and exact volumes to mix two solutions of different concentrations. Supports %, mg/mL, molarity and any unit. Instant results.
Open Bleach Dilution Calculator Calculate how much bleach and water to mix for any ppm, percent, or ratio target. Covers sanitizing, disinfection, mold, and emergency water treatment with CDC-aligned ranges.
Open Buffer Capacity Calculator Calculate buffer capacity (beta) using the Van Slyke equation. Enter pKa, total concentration and pH to get beta, component ratio, and water contribution instantly.
Open Buffer pH Calculator Calculate buffer solution pH instantly using the Henderson-Hasselbalch equation. Enter pKa, acid and base concentrations, or solve for the ratio needed to hit a target pH.
Open Concentration Calculator Calculate solution concentration as molarity, molality, mass percent, volume percent, ppm or ppb. Instant results with step-by-step working shown.
Open Dilution Factor Calculator Solve C1V1=C2V2 for any unknown, switch concentration and volume units freely, and plan a full serial dilution series with per-step volumes in one place.
Open Henderson-Hasselbalch Calculator Solve the Henderson-Hasselbalch equation in any direction: find buffer pH, the base-to-acid ratio, or the pKa from any two known values. Covers acid and base buffers.
Open Mass Percent Calculator Calculate mass percent (% w/w) four ways: component/total, solute+solvent, reverse-solve for component mass, or reverse-solve for total mass. Steps shown.
Open Mixing Ratio Calculator Calculate exact component amounts from any mixing ratio. Enter A:B parts and total quantity, or reverse-solve the ratio from known amounts. Includes percentage breakdown.
Open Neutralization Calculator Calculate acid-base neutralization using MaVana = MbVbnb. Solve for volume, molarity, or equivalents for any acid/base pair in mL or L.
Open Percentage Concentration to Molarity Calculator Convert w/w, w/v, or v/v percentage concentration to molarity (mol/L) instantly. Supports 14 common reagents with preset molar masses and bidirectional calculation.
Open pH Calculator Calculate pH from H+ concentration, weak acid Ka, weak base Kb, Henderson-Hasselbalch buffer, or reverse-solve pH to find [H+] and [OH-].
Open Raoult's Law Calculator Calculate partial pressures, total vapor pressure, and vapor-phase composition for ideal binary mixtures using Raoult's Law. Instant results with step-by-step working.
Open Reconstitution Calculator: Concentration, Volume, and Dose Draw Calculate reconstitution concentration, diluent volume, or solute mass. Enter any two of the three variables to get the third, plus the exact draw volume for your dose.
Open Saponification Value Calculator Calculate the saponification value of any fat or oil from back-titration data. Supports KOH and NaOH, shows step-by-step work, and compares your result to 20 common oils.
Open Serial Dilution Calculator Calculate transfer and diluent volumes for any serial dilution. Supports dilution factor and concentration range modes with a step-by-step protocol.
Open Solution Dilution Calculator Solve for any variable in C1V1 = C2V2 instantly. Supports molar (fM to M) and percent concentrations, six volume units, and step-by-step working for lab prep.
Open TDS Calculator Calculate total dissolved solids (TDS) from electrical conductivity or by summing ion concentrations. Instant ppm rating, WHO/EPA quality band, and suitability guide.
Open Titration Calculator Solve acid-base titrations instantly. Find concentration, volume, equivalence-point pH, half-equivalence pH, and get an indicator recommendation.
Open Water Hardness Calculator Calculate water hardness from calcium and magnesium ions, or convert any hardness reading between ppm, grains per gallon, German, French, Clark degrees, and mmol/L.
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Stoichiometry 14
AFR Calculator (Air-Fuel Ratio) Calculate the air-fuel ratio (AFR), lambda (lambda), equivalence ratio (phi), and percent excess air for gasoline, diesel, ethanol, methane, hydrogen, and more.
Open Atom Economy Calculator Calculate atom economy, E-factor, waste %, and overall process efficiency. Enter up to 4 reagents individually, pick reactant or product-based mode, add percent yield.
Open Avogadro's Number Calculator: Moles, Particles and Mass Convert between moles, number of particles, and mass using Avogadro's constant (6.022 x 10^23). Enter any two values and solve instantly, with step-by-step working.
Open Dilution Calculator Solve any dilution problem: find stock volume, final volume, or either concentration. Supports nM to M, mg/mL, %, nL to L, and serial dilution tables.
Open Grams to Moles Calculator Convert grams to moles or moles to grams with unit switches (mg, kg, mmol, umol). Pick a substance or enter any molar mass. Includes particle count and steps.
Open Hydrogen Ion Concentration Calculator Convert pH to [H+] concentration or [H+] to pH instantly. Also calculates pOH, [OH-], Kw at any temperature, and classifies your solution as acid or base.
Open Molality Calculator Calculate molality (mol/kg) from moles or mass of solute, convert molarity to molality, and find freezing-point depression and boiling-point elevation instantly.
Open Molar Mass of Gas Calculator Calculate the molar mass of any gas from its pressure, volume, temperature, and sample mass using PV=nRT. Supports real-gas correction with compressibility factor Z.
Open Molarity Calculator Calculate molarity, mass, or volume for any solution. Supports M, mM, uM, nM units, reverse-solve mode, and a common-chemicals molar mass table.
Open Mole Calculator Mole calculator with 4 modes: mass/molar mass, particle count, solution molarity, and ideal gas law. Instant results with worked steps and unit options.
Open Mole Fraction Calculator Find the mole fraction of 2 or 3 components by entering moles, masses, or gas partial pressures. Outputs mole percent, molality, and Raoult's law vapor pressure.
Open Molecular Weight Calculator Calculate molecular weight (molar mass) from any chemical formula instantly. Get elemental composition, percent breakdown, and a step-by-step worked solution.
Open Normality Calculator Calculate solution normality (N), find mass needed for a target N, back-solve molarity or volume. Presets for HCl, H2SO4, KMnO4 and more.
Open PPM to Molarity Calculator Convert ppm or ppb to molarity (mol/L, mM, uM) instantly. Supports solvent density adjustment, reverse conversion from molarity to ppm, and 9 common substances.
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General Chemistry 12
Atom Calculator Find protons, neutrons, electrons, mass number, ionic charge and subatomic mass for any element or custom isotope. Includes electron shell config and worked steps.
Open Atomic Mass Calculator Calculate atomic mass from protons and neutrons, or find the average atomic mass from up to 5 isotopes and their abundances. Results in amu, daltons, and kg.
Open Average Atomic Mass Calculator Calculate average atomic mass from up to 5 isotopes. Load element presets, normalize abundances, or reverse-solve for a missing isotope abundance. Shows all work.
Open Bond Order Calculator Calculate bond order using MO theory, Lewis structure counting, or resonance averaging. Shows worked steps, a diatomic reference table, and bond type interpretation.
Open Chemical Name Calculator: IUPAC Naming for Ionic, Covalent, Acid, and Hydrate Compounds Name any ionic, covalent, acid, or hydrate compound instantly. Select ions or enter a formula and get the IUPAC name, charge balance, subscripts, and step-by-step working.
Open Effective Nuclear Charge Calculator Calculate effective nuclear charge (Z-eff) for any element using Slater's rules. Full shielding breakdown, worked steps, and periodic trends for all 118 elements.
Open Electron Configuration Calculator Find the full and noble-gas shorthand electron configuration for any element or ion. Shows valence electrons, shell breakdown, and handles all Aufbau exceptions.
Open Electronegativity Calculator Find the electronegativity difference between two elements, identify bond type (covalent, polar covalent, or ionic), and get percent ionic character on the Pauling scale.
Open Molar Mass Calculator Enter any chemical formula to get molar mass in g/mol, percent composition, moles from mass, grams from moles, molecules, and an ideal-gas reverse-solve.
Open Percent Composition Calculator Find the percent composition by mass of every element in a compound. Enter a chemical formula or raw masses to get a full element-by-element breakdown instantly.
Open Percent Ionic Character Calculator Calculate the percent ionic character of any bond using Pauling's electronegativity formula or the dipole moment method. Bond-type classification with worked steps.
Open pKa Calculator Convert Ka to pKa, pKa to Ka, or find pKa from pH using the Henderson-Hasselbalch equation. Includes a functional group reference table and acid strength gauge.
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Chemical Thermodynamics 11
Boiling Point at Altitude Calculator Find the boiling point of water at any altitude or pressure. Uses the Antoine equation and barometric formula. Metric and imperial, instant results.
Open Boiling Point Calculator Calculate the boiling point of water at any altitude or pressure, or find the boiling point elevation of a solution. Metric and imperial, instant results.
Open Boiling Point Elevation Calculator Calculate boiling point elevation with ΔTb = i·Kb·m. Pick a solvent preset, choose a solute, enter mass or molality, and reverse-solve for any variable.
Open Entropy Calculator Calculate entropy change four ways: heat/temperature (Q/T), reaction (products minus reactants), isothermal ideal gas, or Gibbs free energy. Full worked steps included.
Open Freezing Point Depression Calculator Calculate freezing point depression (ΔTf = i·Kf·m), find the new freezing point, reverse-solve for molality or molar mass. Supports 8 solvents and Fahrenheit.
Open Gibbs Free Energy Calculator Calculate Gibbs free energy (ΔG) from ΔH, T, ΔS; solve for any variable; find ΔG° from K or ΔG from Q. Celsius, Fahrenheit, and calorie unit support.
Open Gibbs' Phase Rule Calculator Calculate thermodynamic degrees of freedom with the Gibbs phase rule. Supports reactive systems, fixed T or P constraints, and all common phase equilibria.
Open Heat of Combustion Calculator Calculate heat of combustion from calorimetry data or standard formation enthalpies. Get results in kJ/mol, kJ/g and MJ/kg with a step-by-step worked solution.
Open STP Calculator (Standard Temperature and Pressure) Convert any gas volume to STP, NTP or SATP instantly. Calculates moles, molar volume and gas density for all four IUPAC standard-condition definitions.
Open Vapor Pressure Calculator Calculate vapor pressure with the Antoine equation for common substances or custom constants, Clausius-Clapeyron, or Raoult law, in mmHg, kPa, atm, Pa, or bar.
Open Vapor Pressure of Water Calculator Calculate the saturation vapor pressure of water at any temperature using the Buck, Magnus, Tetens, Antoine, or Simple formula, in kPa, mmHg, atm, bar, or psi.
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Chemical Reactions 10
Activation Energy Calculator Find activation energy from two rate constants and temperatures, or predict k at a new temperature. Arrhenius equation with step-by-step working and unit conversion.
Open Actual Yield Calculator Calculate actual yield, theoretical yield, or percent yield. Switch between grams and moles, see step-by-step working, and learn the chemistry behind reaction efficiency.
Open Arrhenius Equation Calculator Solve the Arrhenius equation for k, Ea, or k2 instantly. Three modes, step-by-step working, per-mole or per-molecule basis, and a live ln(k) vs 1/T plot.
Open Equilibrium Constant Calculator Calculate Kc or Kp for any reaction, convert between them, find delta G from K, and compare Q vs K to see which way the reaction runs.
Open Kp Calculator Calculate Kp, the equilibrium constant in terms of partial pressures. Convert Kc to Kp using temperature and delta-n, or enter partial pressures directly.
Open Molar Ratio Calculator Find the molar ratio between two substances, convert moles or masses using balanced equation coefficients. Step-by-step stoichiometry shown instantly.
Open Percent Yield Calculator Calculate percent yield or reverse-solve for actual or theoretical yield in mg, g, or kg. Supports moles mode, shows percent loss, and grades reaction efficiency.
Open Rate Constant Calculator Find the rate constant k for 0th, 1st, or 2nd order reactions using the integrated rate law or an experimental rate. Includes half-life and a decay chart.
Open Reaction Quotient Calculator (Qc and Qp) Calculate Qc (concentration-based) or Qp (partial-pressure-based) reaction quotient, compare to K, find logQ, and predict shift direction with step-by-step working.
Open Theoretical Yield Calculator Calculate theoretical yield in grams, kg, or lb from reactant mass or moles. Add actual yield to get percent yield instantly with step-by-step work shown.
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Organic Chemistry 8
Chemical Oxygen Demand (COD) Calculator Calculate COD from FAS titration data using the dichromate method. Enter blank and sample titrant volumes, FAS normality, and sample size to get mg O2/L instantly.
Open Combustion Analysis Calculator Determine the empirical and molecular formula of an organic compound from combustion data. Handles C/H, C/H/O, and C/H/O/N with a step-by-step worked solution.
Open Combustion Reaction Calculator Balance any C-H-O combustion reaction instantly. Get stoichiometric coefficients, O2 required, CO2 and H2O produced, AFR, heating value, and step-by-step solution.
Open Crude Protein Calculator Calculate crude protein % from Kjeldahl titration data. Enter titrant volumes, concentration, and food type to get nitrogen content and crude protein instantly.
Open Degree of Unsaturation Calculator Calculate the degree of unsaturation (DoU) for any organic compound from C, H, N, O, S, and halogen counts. Instant formula, worked steps, and structure interpretation.
Open Double Bond Equivalent Calculator Calculate the double bond equivalent (DBE) or degree of unsaturation for any organic formula. Supports C, H, O, N, halogens, P, and Si with step-by-step working.
Open Liquid Ethylene Density Calculator Calculate liquid ethylene (C2H4) density by temperature or mass/volume. Get results in kg/m3, g/cm3, and lb/ft3 with the empirical formula and NIST reference data.
Open Radiocarbon Dating Calculator (Carbon-14 Dating) Calculate the radiocarbon age of an organic sample from pMC, fraction remaining, or activity ratio. Get the age in years BP with propagated 1-sigma uncertainty.
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Biochemistry 6
Calibration Curve Calculator Calculate slope, intercept, R-squared, LOD, LOQ and unknown concentrations from your standard curve data. Free online tool with step-by-step math.
Open Enzyme Activity Calculator Calculate enzyme activity (U), specific activity (U/mg), and reaction rate from a spectrophotometric or product-based assay. Step-by-step Beer-Lambert working shown.
Open Isoelectric Point Calculator Calculate the isoelectric point (pI) from pKa values. Covers all 20 amino acids with step-by-step working, net charge at any pH, and a charge vs pH curve.
Open Michaelis-Menten Equation Calculator Calculate reaction velocity, Vmax, Km, or substrate concentration using the Michaelis-Menten equation. Includes saturation curve, step-by-step math, and unit switching.
Open Protein Solubility Calculator Calculate protein solubility (%) from Kjeldahl titration data. Enter blank titer, sample titer, NaOH normality, and sample mass for a step-by-step breakdown.
Open Resuspension Calculator Calculate resuspension volume, concentration, or amount for DNA/RNA oligos and general reagents. Supports nmol, uM, uL, and C1V1=C2V2 dilutions.
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Electrochemistry 5
Cell EMF Calculator - Electromotive Force of a Cell Calculate cell EMF from electrode potentials or the Nernst equation. Get Gibbs free energy, equilibrium constant K, and a reduction potential reference table.
Open Electrolysis Calculator (Faraday's Law) Calculate mass deposited, charge, current, or time with Faraday's law of electrolysis. Element presets, current efficiency, step-by-step math, and a deposition chart.
Open Ionic Strength Calculator Calculate ionic strength from ion concentrations and charges, or pick a salt preset. Includes Debye-Huckel activity coefficients and a step-by-step breakdown.
Open Lattice Energy Calculator Calculate ionic lattice energy using the Born-Lande equation, Kapustinskii approximation, or Born-Haber cycle. Instant results in kJ/mol with step-by-step working.
Open Nernst Equation Calculator Nernst equation calculator: find E, Gibbs free energy deltaG, and equilibrium constant K. Supports half-cell mode, reverse-solve for E0 or Q, and any temperature.
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What Chemistry Calculators Are Used For
Chemistry calculators automate the quantitative work that underlies laboratory experiments, pharmaceutical formulation, industrial chemical processes, and academic coursework. Stoichiometry, molarity, pH, gas laws, and percent yield calculations all follow precise mathematical rules that are straightforward in principle but tedious and error-prone to execute by hand, especially when unit conversions are involved. These tools let chemists and students focus on the science rather than the arithmetic.
Common Uses and Real-Number Examples
- Molarity and solution preparation. To prepare 500 mL of a 0.25 M sodium chloride solution, you need moles = molarity times volume = 0.25 times 0.5 = 0.125 moles of NaCl. Multiplying by the molar mass of NaCl (58.44 g/mol) gives 7.3 grams to dissolve in enough water to reach 500 mL total volume. A molarity calculator walks through each of these steps.
- pH and hydrogen ion concentration. A solution with a hydrogen ion concentration of 0.001 mol/L has a pH of negative log(0.001) = 3, which is acidic. If the pH changes to 5, the hydrogen ion concentration drops to 0.00001 mol/L, a factor of 100 times lower. pH calculators convert between pH, hydrogen ion concentration, and hydroxide ion concentration instantly.
- Stoichiometry and limiting reagents. In the reaction 2H₂ + O₂ → 2H₂O, if you have 4 moles of H₂ and 1.5 moles of O₂, you need a 2:1 mole ratio of H₂ to O₂. Your 4 moles of H₂ would need 2 moles of O₂, but you only have 1.5, so O₂ is the limiting reagent and you can produce at most 3 moles of water.
- Ideal gas law problems. PV = nRT lets you solve for any one variable when the other three are known. If 2 moles of an ideal gas occupy 40 liters at 300 K, the pressure equals nRT/V = (2 × 0.08206 × 300) / 40 = approximately 1.23 atm.
Key Concepts in Plain Language
The mole is chemistry's counting unit: one mole of any element or compound contains about 6.02 × 10²³ particles (Avogadro's number). Molar mass converts between moles and grams, and molarity expresses concentration as moles of solute per liter of solution. pH is a logarithmic scale running from 0 (strongly acidic) to 14 (strongly basic), where 7 is neutral. Because the scale is logarithmic, a change of one pH unit represents a tenfold change in hydrogen ion concentration, which is why small pH shifts can have large effects in biological systems.
What to Look For When Using These Tools
Double-check that you are using the correct molar mass for each element, since isotopes and polyatomic ions have specific masses that differ from the whole-number approximations in periodic tables. For solution preparation, confirm whether the calculator is asking for final volume (the correct interpretation) or the volume of solvent added (slightly different due to dissolved volume). Always verify that the gas law calculator uses consistent pressure units throughout, since mixing atmospheres and kilopascals without conversion is a very common source of error.