The Partial Pressure Calculator determines the pressure contribution of each gas in a mixture using Dalton’s Law of Partial Pressures, which states that the total pressure of a gas mixture equals the sum of the partial pressures of its components. By entering the total pressure and the moles of each gas present, the calculator computes each gas’s partial pressure based on its mole fraction: Pₓ = (nₓ / nₜₒₜₐₗ) × Pₜₒₜₐₗ. This is useful in chemical reactions involving gas mixtures, laboratory calculations, and thermodynamic studies to understand how each gas contributes to the total system pressure.