Chemistry Calculators
167 calculators across all chemistry domains
Molar Mass Calculator
Calculate the molar mass of a compound from atomic masses
M = Σ(nᵢ × Aᵢ)
Molar Mass (Advanced)
Calculate molar mass with more elements
M = Σ(nᵢ × Aᵢ)
Moles from Mass
Calculate moles from mass and molar mass
n = m/M
Mass from Moles
Calculate mass from moles and molar mass
m = n × M
Percent Composition
Calculate mass percent of each element
% = (mass element / total mass) × 100%
Empirical Formula (from percents)
Find empirical formula from mass percentages
Convert % to moles, find ratio
Limiting Reactant
Determine the limiting reactant in a reaction
Compare mole ratios
Theoretical Yield
Calculate theoretical yield from limiting reactant
Yield = moles_product × M_product
Percent Yield
Calculate percent yield of a reaction
% yield = (actual / theoretical) × 100%
Molarity
Calculate molarity, moles, or volume
M = n/V (L)
Dilution (M₁V₁ = M₂V₂)
Calculate dilution concentration or volume
M₁V₁ = M₂V₂
Molality
Calculate molality of a solution
m = moles_solute / kg_solvent
Parts Per Million (PPM)
Calculate concentration in ppm
ppm = (mass_solute / mass_solution) × 10⁶
Enthalpy of Reaction (ΔH)
Calculate enthalpy change using standard enthalpies
ΔH° = ΣΔH°f(products) - ΣΔH°f(reactants)
Gibbs Free Energy (ΔG)
Calculate Gibbs free energy change
ΔG = ΔH - TΔS
Entropy Change (ΔS)
Calculate entropy change
ΔS = Q_rev / T
Calorimetry (q = mcΔT)
Calculate heat absorbed or released
q = mcΔT
Bond Energy
Estimate ΔH using bond energies
ΔH ≈ Σ(bonds broken) - Σ(bonds formed)
Hess's Law
Calculate ΔH from multiple reaction steps
ΔH_total = ΣΔH_steps
Heat of Combustion
Calculate heat released from combustion
q = m × c × ΔT
Standard Enthalpy of Formation
Calculate ΔH°f from standard data
ΔH°f values
Phase Change Energy
Calculate energy for phase transitions
Q = m × ΔH_phase
First-Order Rate Law
Calculate concentration at time t for first-order reaction
ln[A] = -kt + ln[A]₀
Second-Order Rate Law
Calculate concentration at time t for second-order reaction
1/[A] = kt + 1/[A]₀
Arrhenius Equation
Calculate rate constant at a given temperature
k = Ae^(-Ea/RT)
Half-Life (First Order)
Calculate half-life of first-order reaction
t½ = ln(2)/k
Activation Energy (from k, T)
Calculate activation energy from rate constants
Ea = -R × slope of ln(k) vs 1/T
Equilibrium Constant (K)
Calculate equilibrium constant from concentrations
K = [C]^c[D]^d/[A]^a[B]^b
Reaction Quotient (Q)
Calculate Q to predict reaction direction
Q = [C]^c[D]^d/[A]^a[B]^b (current)
Solubility Product (Ksp)
Calculate Ksp from solubility
Ksp = [ion]^n × [ion]^m
ICE Table (Simple)
Calculate equilibrium concentrations
Initial, Change, Equilibrium
pH Calculator
Calculate pH from H⁺ concentration
pH = -log[H⁺]
[H₃O⁺] from pH
Calculate hydronium concentration from pH
[H₃O⁺] = 10^(-pH)
Henderson-Hasselbalch
Calculate pH of a buffer solution
pH = pKa + log([A⁻]/[HA])
Ka from pH
Calculate acid dissociation constant from pH
Ka = [H⁺][A⁻]/[HA]
Weak Base pH
Calculate pH of a weak base solution
[OH⁻] = √(Kb × Cb)
Buffer Capacity
Calculate buffer capacity against added acid/base
β = Δbase/ΔpH
Titration (Strong Acid/Base)
Calculate volume needed for neutralization
M₁V₁ = M₂V₂
Polyprotic Acid Speciation
Dominant species at given pH
Speciation from Ka values
Standard Cell Potential (E°)
Calculate standard cell potential
E°_cell = E°_cathode - E°_anode
Nernst Equation
Calculate cell potential at non-standard conditions
E = E° - (RT/nF)ln(Q)
Faraday's Law (Mass Deposited)
Calculate mass of substance deposited in electrolysis
m = (I × t × M) / (n × F)
Conductivity & Molar Conductivity
Calculate molar conductivity
Λm = κ/c
ΔG from Cell Potential
Calculate Gibbs free energy from cell potential
ΔG = -nFE
Ideal Gas Law (PV = nRT)
Calculate P, V, n, or T for ideal gases
PV = nRT
Combined Gas Law
Calculate P₂, V₂, or T₂
P₁V₁/T₁ = P₂V₂/T₂
Dalton's Law (Partial Pressures)
Calculate total pressure or partial pressure
P_total = ΣP_i
RMS Speed of Gas
Calculate root mean square speed
v_rms = √(3RT/M)
Graham's Law (Effusion)
Compare effusion rates of two gases
Rate₁/Rate₂ = √(M₂/M₁)
Radioactive Decay
Calculate remaining isotope after decay
N = N₀e^(-λt)
Carbon-14 Dating
Calculate age from C-14 remaining
t = -ln(N/N₀)/λ
Beer-Lambert Law (A = εbc)
Calculate concentration from absorbance
A = εbc
LOD & LOQ
Calculate limits of detection and quantification
LOD = 3.3σ/S, LOQ = 10σ/S
Retention Factor (TLC)
Calculate Rf in thin-layer chromatography
Rf = distance_solute/distance_solvent
Chromatographic Resolution
Calculate resolution between two peaks
Rs = 2(t₂-t₁)/(w₁+w₂)
Degree of Unsaturation (DoU)
Calculate double bond equivalents from formula
DoU = C - H/2 - X/2 + N/2 + 1
Enantiomeric Excess
Calculate enantiomeric purity
ee = (R-S)/(R+S) × 100%
Elemental Analysis
Calculate %C, %H from combustion data
%C = mass_CO₂ × 12/M_CO₂ / sample × 100
Synthetic Yield (Overall)
Calculate overall yield of multi-step synthesis
Overall = Π(yields)
Lipinski's Rule of Five
Check drug-likeness using Rule of Five
MW ≤ 500, logP ≤ 5, HBD ≤ 5, HBA ≤ 10
NMR Chemical Shift Estimation
Estimate ¹H NMR chemical shift range
δ from electronegativity
Periodic Trends Calculator
Calculate periodic trends (electronegativity, radius)
Periodic properties
Isotopic Mass Calculator
Calculate average atomic mass from isotopic abundances
Avg = Σ(abundance × mass)
Oxidation Number Calculator
Assign oxidation numbers to elements
Rules for oxidation states
Formal Charge Calculator
Calculate formal charge on an atom
FC = V - N_nonbonding - N_bonding/2
Solution Preparation
Calculate mass or volume needed for solution prep
m = M × V × MW
Normality Calculator
Calculate normality from molarity
N = M × n (n = equivalent factor)
Half-Equivalence Point pH
Calculate pH at half-equivalence of weak acid titration
pH = pKa at half-equivalence
Buffer Ratio [A⁻]/[HA]
Find ratio for desired pH buffer
[A⁻]/[HA] = 10^(pH-pKa)
Half-Life (Zero Order)
Calculate half-life of zero-order reaction
t½ = [A]₀/(2k)
Integrated Rate Law (Zero Order)
Calculate concentration at time t (zero order)
[A] = [A]₀ - kt
Electrolysis Time Calculator
Calculate time required for electrolysis
t = (n × F × m)/(M × I)
Quantum Yield (Photochemistry)
Calculate quantum yield of a photochemical reaction
Φ = molecules_reacted / photons_absorbed
Reaction Rate Constant
Calculate rate constant from concentration data
k = (1/t)ln([A]₀/[A]) for first order
Atomic Absorption (Beer-Lambert)
Calculate concentration from atomic absorption
A = εbc
Titration Curve pH (Strong Acid + Strong Base)
Calculate pH during strong acid/strong base titration
pH based on excess H⁺ or OH⁻
Reduction Potential (from ΔG)
Calculate reduction potential from Gibbs free energy
E° = -ΔG/(nF)
Lattice Energy (Kapustinskii)
Estimate lattice energy using Kapustinskii equation
U = K × ν/Z × Z₊Z₋/r₀ × (1 - d/r₀)
Polymer Dispersity (PDI)
Calculate PDI from number and weight average MW
PDI = M_w / M_n
Schotten-Baumann Yield
Calculate yield in Schotten-Baumann reaction
% yield = actual/theoretical × 100
Crystal Field Splitting
Calculate crystal field stabilization energy (CFSE)
CFSE = -0.4Δ₀ × n_t2g + 0.6Δ₀ × n_eg
Mole Fraction
Calculate mole fraction and molality
X_A = n_A / (n_A + n_B)
Raoult's Law (Vapor Pressure)
Calculate vapor pressure of solution
P = X_solvent × P°_solvent
Boiling Point Elevation
Calculate boiling point elevation
ΔT_b = i × K_b × m
Freezing Point Depression
Calculate freezing point depression
ΔT_f = i × K_f × m
Osmotic Pressure
Calculate osmotic pressure using van't Hoff equation
Π = iMRT
Arrhenius Equation (Two Points)
Calculate activation energy from two rate constants
Ea = R × ln(k₂/k₁)/(1/T₁-1/T₂)
Standard Free Energy (ΔG°)
Calculate standard Gibbs free energy change
ΔG° = -RT ln(K)
van der Waals Equation
Calculate pressure using van der Waals equation
(P + an²/V²)(V - nb) = nRT
Conjugate Acid-Base Pair
Find pKa of conjugate acid from conjugate base pKb
pKa + pKb = 14
Polyprotic Acid pH (Diprotic)
Calculate pH of diprotic acid solution
First dissociation dominates
Autoionization of Water (Kw)
Calculate H⁺ and OH⁻ from Kw at T
Kw = [H⁺][OH⁻]
Percent Error in Yield
Calculate percent error in experimental yield
% Error = |theoretical-actual|/theoretical × 100%
Mass Percent Composition
Calculate mass percent of each element in a compound
% = (n×A/MW) × 100%
pH of Strong Acid
Calculate pH of a strong acid solution
pH = -log[H⁺]
Oxidation Number Change (Redox)
Calculate electron transfer in redox reactions
Electrons transferred = change in oxidation state
Third-Order Rate Law (Integrated)
Calculate concentration for third-order reaction
1/[A]² = 2kt + 1/[A]₀²
Zero-Order Rate Law (Integrated)
Calculate concentration for zero-order reaction
[A] = [A]₀ - kt
Colligative Properties (Summary)
Calculate boiling point, freezing point, and osmotic pressure
ΔT_b, ΔT_f, Π
Gas Volume at STP
Calculate volume of gas at STP from moles
V = n × 22.4 L
Avogadro's Number Calculator
Calculate number of atoms/molecules from moles
N = n × N_A
Reconstitution Calculator
Calculate volume needed to reconstitute a powder to desired concentration
V = mass / concentration
Water Hardness Calculator
Calculate water hardness as CaCO₃ equivalent
Hardness = (Ca × 2.5) + (Mg × 4.12)
Bond Order Calculator
Calculate bond order from molecular orbital electron counts
BO = (bonding − antibonding) / 2
Effective Nuclear Charge (Zeff)
Calculate Zeff using Slater's rules
Zeff = Z − S
Percent Ionic Character
Calculate % ionic character from electronegativity difference
% IC = 100 × (1 − e^(−0.25Δχ²))
Atom Economy Calculator
Calculate atom economy of a chemical reaction
AE = (MW_desired / ΣMW_reactants) × 100%
Ionic Strength Calculator
Calculate ionic strength of a solution
I = ½Σcᵢzᵢ²
Q10 Temperature Coefficient
Calculate Q10 temperature coefficient for reaction rates
Q10 = (R₂/R₁)^(10/(T₂−T₁))
Concentration Converter
Convert between % concentration, molarity, and ppm
M = (10 × d × %)/MW, ppm = % × 10,000
Chemical Oxygen Demand (COD)
Calculate COD from dichromate consumption
COD = (V_blank − V_sample) × M × 8000 / V_sample
Crude Protein Calculator (Kjeldahl)
Calculate crude protein from nitrogen content
Protein = N × 6.25
Molar Ratio Calculator
Calculate molar ratios between reactants and products
Ratio = n_A / n_B
Boiling Point at Altitude
Calculate water boiling point at different altitudes
BP = 100 − 0.0033 × h
Activity Coefficient (Debye-Hückel)
Calculate mean ionic activity coefficient
log γ = −A|z⁺z⁻|√I/(1 + B√I)
Saponification Value Calculator
Calculate saponification number for soap making
SV = (mg KOH) / (g fat)
TDS from Conductivity
Calculate Total Dissolved Solids from electrical conductivity
TDS = k × EC (k ≈ 0.64)
Alligation Calculator
Calculate mixing ratio of two solutions to achieve target concentration
Parts = |target − conc₂| : |target − conc₁|
pKa / Ka Converter
Convert between Ka and pKa values
pKa = −log₁₀(Ka), Ka = 10^(−pKa)
AFR Calculator (Air-Fuel Ratio)
Calculate stoichiometric air-fuel ratio from fuel composition
AFR = (O₂_needed × 4.76) / fuel_mass
Atom Calculator
Calculate basic atom counts from atomic number and mass number.
neutrons = mass_number - atomic_number
Atomic Mass Calculator
Estimate atomic mass from protons and neutrons.
atomic_mass = protons + neutrons
Average Atomic Mass Calculator
Calculate weighted average atomic mass from two isotopes.
avg = m1 x f1 + m2 x f2
Chemical Name Calculator
Estimate ionic compound subscripts from ion charges.
subscripts from charge crossover
Electron Configuration Calculator
Estimate shell electron counts from atomic number.
fill shells 2, 8, 18, 32
Electronegativity Calculator
Calculate electronegativity difference and bond polarity estimate.
delta = abs(EN1 - EN2)
Quiz: Electron Configuration Calculator
Check electron totals across shells.
score = matching electrons / atomic number
Grams to Moles Calculator
Convert grams to moles using molar mass.
n = mass / molar_mass
Molar Mass of Gas Calculator
Calculate gas molar mass using the ideal gas law.
M = mRT / PV
Mole Calculator
Convert between moles, mass, and particles.
mass = nM, particles = nNA
Molecular Weight Calculator
Estimate molecular weight from C, H, N, O, and S atom counts.
MW = sum atoms x atomic masses
Moles to Atoms Converter
Convert moles to atoms or formula units.
atoms = moles x Avogadro number
PPM to Molarity Calculator
Convert ppm concentration to molarity for dilute aqueous solutions.
M = ppm / (1000 x MW)
Bleach Dilution Calculator
Calculate stock bleach volume for a target dilution.
C1V1 = C2V2
Dilution Factor Calculator
Calculate dilution factor from stock and final volumes.
DF = final_volume / aliquot_volume
Mixing Ratio Calculator
Calculate mixture concentration from two solution volumes.
Cmix = (C1V1 + C2V2)/(V1+V2)
Neutralization Calculator
Calculate neutralization volume using equivalents.
acid_eq = base_eq
Percent Solution Calculator
Calculate mass/volume percent solution.
% = solute mass / solution volume
Serial Dilution Calculator
Calculate final concentration after repeated dilutions.
Cfinal = C0 / DF^steps
Solution Dilution Calculator
Calculate final molarity after dilution.
M2 = M1V1/V2
Actual Yield Calculator
Calculate actual yield from percent yield and theoretical yield.
actual = percent_yield x theoretical
Chemical Equation Balancer
Balance hydrocarbon combustion from CxHyOz.
CxHyOz + O2 -> CO2 + H2O
Kp Calculator
Convert Kc to Kp for gas reactions.
Kp = Kc(RT)^delta_n
Net Ionic Equation Calculator
Estimate net ionic reacting equivalents after removing spectator amounts.
net = min(cation eq, anion eq)
Rate Constant Calculator
Calculate a rate constant from rate law data.
k = rate / product concentrations^orders
Boiling Point Calculator
Estimate boiling point from vapor pressure using a simple Clausius-Clapeyron form.
1/Tb = 1/Tref - R ln(P/Pref)/dHvap
Gibbs' Phase Rule Calculator
Calculate degrees of freedom for a phase system.
F = C - P + 2
STP Calculator (Standard Temperature and Pressure)
Calculate gas volume at STP from moles.
V = n x 22.414 L
Vapor Pressure Calculator
Estimate vapor pressure with the Antoine equation.
log10(P) = A - B/(C + T)
Vapor Pressure of Water Calculator
Estimate water vapor pressure from temperature.
Antoine equation for water
Diffusion Coefficient Calculator
Estimate diffusion coefficient from mean squared displacement.
D = MSD / (2nt)
Langmuir Isotherm Calculator
Calculate surface coverage from Langmuir adsorption.
theta = KP/(1 + KP)
Two-Photon Absorption Calculator
Estimate two-photon absorption rate from intensity.
rate = delta x I^2
Young-Laplace Equation Calculator
Calculate pressure difference across a curved interface.
deltaP = gamma(1/R1 + 1/R2)
Combustion Analysis Calculator
Estimate empirical mole ratios from CO2 and H2O masses.
C from CO2, H from H2O
Combustion Reaction Calculator
Balance complete combustion for CxHyOz.
fuel + O2 -> CO2 + H2O
Liquid Ethylene Density Calculator
Estimate liquid ethylene density from mass and volume.
rho = mass / volume
Calibration Curve Calculator
Calculate concentration from a linear calibration curve.
x = (signal - intercept) / slope
Enzyme Activity Calculator
Calculate enzyme activity from product formed over time.
activity = product / time
Isoelectric Point Calculator
Estimate pI from acidic and basic pKa values.
pI = average neighboring pKa values
Michaelis-Menten Equation Calculator
Calculate enzyme reaction velocity.
v = Vmax[S]/(Km + [S])
Protein Solubility Calculator
Estimate soluble protein mass from solubility and volume.
mass = solubility x volume
Resuspension Calculator
Calculate buffer volume for a target stock concentration.
V = mass / concentration
Cubic Cell Calculator
Calculate cubic unit cell volume and density.
rho = ZM / (NA a^3)
Detention Time Calculator
Calculate tank detention time from volume and flow.
time = volume / flow
Hydraulic Retention Time Calculator
Calculate hydraulic retention time.
HRT = reactor volume / influent flow
Miller Indices Calculator
Convert intercepts to Miller index reciprocals.
h:k:l = 1/a : 1/b : 1/c