Math Expression Evaluator
Evaluate mathematical expressions with functions and constants.
Overview
The Math Expression Evaluator parses and evaluates a free-form mathematical expression with operators, parentheses, common functions and constants. Type something like sin(pi/4) + sqrt(2) and read off the value — no need to break it into discrete calculator steps.
It is built for engineers running quick what-ifs, students checking algebra by substituting numbers and developers prototyping formulae. Anywhere a calculator app would force you to clear the stack and start over, the evaluator lets you write the expression as it appears on paper.
How it works
The input is tokenised, converted to postfix using the shunting-yard algorithm and evaluated on a stack. Supported operators include + - * / ^ with standard precedence, parentheses for grouping, and unary minus. Functions include sin, cos, tan, asin, acos, atan, exp, ln, log, sqrt, abs, floor, ceil and round.
Constants pi, e, tau and phi are recognised. Angles are interpreted in radians by default; if you prefer degrees, use the radians(d) conversion or compute manually with pi / 180.
Examples
2 + 3 * 4 → 14
(1 + sqrt(5)) / 2 → ≈ 1.6180339887 (the golden ratio)
sin(pi / 6) → 0.5
log(1000) / log(2) → ≈ 9.9658 (log base 2 of 1000)
FAQ
Are trig functions in degrees or radians?
Radians by default. To use degrees, write sin(30 * pi / 180) or wrap with a conversion helper.
What's the difference between log and ln?
log is base 10; ln is base e. Use log(x) / log(b) for any other base.
Can it solve equations?
No — it evaluates expressions only. For root finding, see the Quadratic, Cubic or Numerical Integration tools.
Is there a variable feature?
This evaluator works with constants and literals. The Equation Plotter accepts a free x variable and plots the result.
What happens with invalid syntax?
The parser stops at the first error and shows where it tripped up. Common issues are mismatched parentheses or unknown function names.