🧮Calculator Free online calculator — Standard and Scientific modes. Arithmetic, trigonometry, logarithms, powers, factorials and more. How To Use: Toggle between Standard and Scientific at the top. Standard mode: type numbers and operators, press = to evaluate. Scientific mode adds sin, cos, tan, log, ln, powers, factorial, constants (π, e), and Deg/Rad toggle. Use AC to clear, ⌫ to backspace, and ± to negate. Why Use This Tool Free online calculator with Standard and Scientific modes — worldwide-standard operations, clean UI, keyboard support, dark mode, and no signup.