Gibbs Phase Rule Calculator
Calculate degrees of freedom using Gibbs Phase Rule (F = C - P + 2). Determine variance for any system with multiple components and phases, with interactive phase diagram examples.
Free Acids & Bases Calculators
6 toolspH, pKa, Henderson-Hasselbalch, and neutralization calculators. Browse our free acids & bases tools below — no sign-up required.
Henderson-Hasselbalch Calculator
Calculate buffer pH using the Henderson-Hasselbalch equation. Determine pH from pKa and concentration ratio, or solve for any variable. Includes buffer capacity and common buffer recipes.
Neutralization Reaction Calculator
Calculate volumes, concentrations, and heat of neutralization for acid-base reactions. Supports strong/strong, strong/weak, and polyprotic acid reactions with stoichiometry.
pH Calculator
Calculate pH, pOH, [H⁺], and [OH⁻] from any one value. Includes strong/weak acid-base calculations, dilution, and a visual pH scale with common substance comparisons.
pKa Calculator
Convert between pKa and Ka, calculate conjugate pKb, predict acid strength, and compare acid-base properties. Includes a database of common acids with pKa values and polyprotic acid support.
Two-Photon Absorption Calculator
Calculate two-photon absorption cross-sections, excitation wavelengths, action cross-sections, and fluorescence rates. Covers GM units, power density, and comparison of TPA fluorophores.