Chemistry

  • Atoms to Moles Calculator
    Convert a number of atoms or particles to moles instantly using Avogadro's number (6.022 × 10²³). Free, accurate chemistry conversion tool.
  • Concentration to Absorbance Calculator
    Calculate absorbance from concentration using the Beer-Lambert law (A = ε·c·l). Enter molar absorptivity, concentration and path length to get A and %T.
  • pH After Dilution Calculator
    Calculate the pH of a strong acid or base after dilution. Enter C1, V1 and V2 to get the diluted concentration C2, pH and pOH instantly.
  • Radioactivity Unit Conversion Calculator
    Convert radioactivity between Becquerel (Bq) and Curie (Ci) units. Enter an activity value and see all 12 SI and Curie-family units at once. 1 Ci = 3.7e10 Bq.
  • Osmolarity Calculator
    Calculate solution osmolarity in Osmol/L and mOsmol/L from solute molarity and the van't Hoff factor (number of dissociated particles).
  • Radiation Exposure Unit Conversion Calculator
    Convert radiation exposure between Roentgen (R, mR, uR) and Coulomb per kilogram (C/kg, mC/kg, uC/kg) using the exact 1 R = 2.58e-4 C/kg definition.
  • CFU/mL Calculator
    Calculate colony-forming units per mL (CFU/mL) from plate counts, dilution factor and volume plated. Free, instant microbiology bacterial count tool.
  • Wavenumber Calculator
    Calculate wavenumber from wavelength. Angular k = 2π/λ (rad/m) or spectroscopic ν̃ = 1/λ (1/m and 1/cm). Supports nm, µm, mm, cm, m.
  • Wavelength to Frequency Calculator
    Convert wavelength to frequency instantly using f = c / λ with the speed of light c = 2.998×10⁸ m/s. Supports nm, µm, mm, cm, and m units.
  • Thermal Energy Calculator
    Calculate thermal energy (heat) Q with the formula Q = m·c·ΔT. Enter mass, specific heat, and temperature change to get energy in joules and kJ.
  • Root Mean Square Velocity Calculator
    Calculate the root mean square (RMS) velocity of gas molecules from temperature and molar mass using v_rms = sqrt(3RT/M). Fast, accurate, free.
  • Sensible Heat Calculator
    Calculate sensible heat with Q = m·c·ΔT. Enter mass, specific heat, and temperature change to find energy in joules and kilojoules.
  • Specific Gas Constant Calculator
    Calculate the specific gas constant Rspecific = R/M from molar mass. Universal R = 8.314 J/mol·K. Instant J/(kg·K) result with worked example.
  • Latent Heat Calculator
    Calculate the latent heat energy (Q = m × L) for a phase change using mass and specific latent heat. Free online physics calculator with results in J and kJ.
  • Ideal Gas Density Calculator
    Calculate the density of an ideal gas from pressure, molar mass, and temperature using ρ = PM/(RT). Fast, accurate, with worked examples.
  • Gay-Lussac's Law Calculator
    Solve Gay-Lussac's Law (P1/T1 = P2/T2) for pressure or temperature of a gas at constant volume. Enter three values to find the fourth. Use Kelvin.
  • Electrical Mobility Calculator
    Calculate electrical mobility μ from charge, relaxation time and effective mass using μ = qτ/m. Free physics tool with worked example and formula.
  • Heat Capacity Calculator
    Calculate heat capacity (C) from heat energy (Q) and temperature change (ΔT) using C = Q / ΔT. Free physics tool with worked example and FAQ.
  • Compressibility Factor Calculator
    Calculate the gas compressibility factor Z = PV/(nRT) from pressure, volume, moles, and temperature. Free, instant, with full worked example.
  • Curie's Law Calculator
    Calculate magnetization with Curie's Law M = C·B/T from the Curie constant, magnetic field, and absolute temperature. Free physics calculator.
  • Charles' Law Calculator
    Free Charles' Law calculator. Solve for the final gas volume V₂ from V₁/T₁ = V₂/T₂ using Kelvin temperatures. Fast, accurate, with worked example.
  • Calorimetry Calculator
    Calculate heat energy (Q) absorbed or released using Q = m·c·ΔT. Enter mass, specific heat, and temperature change to get joules instantly.
  • Quantum Numbers Calculator
    Enter the principal quantum number n to find the allowed l and mₗ values, number of subshells, orbitals, and maximum electrons (2n²) in a shell.
  • Rydberg Equation Calculator
    Calculate the wavelength, wavenumber, and frequency of hydrogen spectral lines using the Rydberg equation 1/λ = R(1/n₁² − 1/n₂²).

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