by Mark Logarithm CalculatorLogarithm Calculator Number (x) Must be a positive number Base (b) Base must be positive and ≠ 1 Log₁₀ (Common) Logₑ (Natural) Custom BaseLogarithm Propertieslogₐ(xy) = logₐx + logₐylogₐ(x/y) = logₐx – logₐylogₐ(xⁿ) = n·logₐxlogₐa = 1logₐ1 = 0