Expression Calculator

Need to evaluate a complex mathematical formula without doing it by hand? An expression calculator interprets a string of mathematical input – from simple arithmetic to nested functions – and gives you the exact numeric answer. The free online tool below lets you type any valid mathematical expression and get the result instantly.

Start by entering a calculation: 2 + 3 * sin(pi/4), sqrt(16) + log(100), or even a custom expression with variables like x = 5; 2 * x^2 - 3*x + 1. The calculator parses your input according to standard mathematical rules and returns the final value.

Expression Calculator Type any expression with operators (+, -, *, /, ^, %), functions, and constants. Use ; to separate multiple expressions. Assign variables with = (e.g., x = 5). All trigonometric functions expect angles in radians.
Quick Insert
Supported Functions & Constants
CategoryFunctions
Trigonometricsin(x), cos(x), tan(x), asin(x), acos(x), atan(x)
Hyperbolicsinh(x), cosh(x), tanh(x)
Exponential & Logexp(x), ln(x), log(x) (base 10), log10(x)
Power & Rootsqrt(x), pow(x, y)
Roundingabs(x), round(x), floor(x), ceil(x)

Constants: pi (π ≈ 3.1415926535), e (≈ 2.7182818284)

Operator Precedence
PriorityOperators / Elements
1 (highest)Parentheses ()
2Unary minus, functions
3Exponentiation ^ (right‑associative)
4Multiplication *, division /, modulo %
5 (lowest)Addition +, subtraction -
Examples
  • 2+3*414 (multiplication before addition)
  • (2+3)*420 (parentheses change order)
  • sin(pi/2)1 (radians assumed)
  • sqrt(16)+log(100)6 (√16 = 4, log₁₀100 = 2)
  • 2^3^2512 (right‑associative: 2^(3²))
  • x=10; 2*x20 (variable assignment)

How to Use the Expression Calculator?

The expression calculator above reads the text you enter, identifies numbers, operators, functions, and constants, and evaluates them following the conventional order of operations. Here are the basics:

  • Type any expression using digits, operators (+, -, *, /, ^), parentheses, and supported function names.
  • Assign variables with = if needed (the variable must appear on the left side, e.g., a = 10), then use it in subsequent expressions.
  • Watch the result – the calculator computes the value and displays it as soon as the input is valid. No need to press a separate button (though a “Calculate” action may be available for clarity).
  • Fix mistakes – if there’s a syntax error, the tool shows a brief message; simply adjust your input.

The calculator respects standard precedence: parentheses have the highest priority, followed by functions and exponentiation, then multiplication / division, and finally addition / subtraction.

Supported Mathematical Functions

The expression calculator includes built-in elementary functions that go far beyond basic arithmetic. All trigonometric functions expect angles in radians.

CategoryFunctions
Trigonometricsin(x), cos(x), tan(x), asin(x), acos(x), atan(x)
Hyperbolicsinh(x), cosh(x), tanh(x)
Exponential & Logexp(x), ln(x), log(x) (base 10), log10(x)
Power & Rootsqrt(x), pow(x, y) (equivalent to x^y)
Roundingabs(x), round(x), floor(x), ceil(x)

You can also directly use constants:

  • pi – the number π (≈ 3.1415926535)
  • e – Euler’s number (≈ 2.7182818284)

Operator Precedence and Syntax Rules

When you type 2+3*4, the calculator understands that multiplication comes before addition and returns 14, not 20. Below is the full precedence table, from highest to lowest priority.

PrecedenceOperators / Elements
1 (highest)Parentheses ()
2Unary minus -, functions
3Exponentiation ^ (right‑associative)
4Multiplication *, division /, modulo %
5 (lowest)Addition +, subtraction -

Exponentiation is right‑associative, so 2^3^2 is interpreted as 2^(3^2) = 512. Use parentheses to make the order explicit when needed.

Expressions That Often Confuse

Here are a few examples that illustrate common patterns – and how the expression calculator handles them.

  • 2+3*414 (multiplication first)
  • (2+3)*420 (parentheses change order)
  • sin(pi/2)1 (radians assumed)
  • sqrt(16)+log(100)6 (square root = 4, log base 10 = 2)
  • 2^3^2512 (right‑associative exponentiation)
  • x=10; 2*x20 after the assignment (semicolons separate multiple expressions)

What If the Expression Contains Errors?

If you miss a closing parenthesis, write an unknown function name, or use symbols incorrectly, the expression calculator will flag the problem. A short error message appears, pointing out the likely issue – for example, “Unexpected token” for a stray operator, or “Undefined function” for a misspelled word. Correct the input and the calculation automatically updates.

The error messages are designed to be simple and actionable, so you can quickly get back to the math you need.

Frequently Asked Questions

What is an expression calculator?
An expression calculator is a tool that parses and evaluates mathematical expressions entered as text, such as “2 + 3 * sin(pi/4)”. It understands order of operations, built-in functions, and constants to return a numeric result.
Does the expression calculator support trigonometric functions?
Yes, the calculator supports standard trigonometric functions including sine, cosine, tangent, and their inverses. Angles are expected in radians unless you use degree-specific functions if available.
Can I use variables in the expression?
The calculator allows you to assign values to variable names like x or y and then use them in expressions. This is useful for evaluating formulas with adjustable parameters.
What symbols are used for exponents and roots?
Use the caret (^) for exponentiation, e.g., 2^3 = 8. For square roots, use the sqrt() function, and for nth roots, use power notation like x^(1/n).
Are there any built-in constants?
Yes, common mathematical constants like pi (π) and e (Euler’s number) are recognized. Enter them as “pi” and “e” in your expressions.
What happens if I enter an invalid expression?
If the expression contains syntax errors or undefined functions, the calculator will show an error message indicating the problem. You can then correct the input and recalculate.
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