Math Expression Evaluator
Type a math expression and get the result instantly. Supports arithmetic, functions, and constants.
About This Tool
The Math Expression Evaluator is a browser-based calculator that
evaluates arbitrary mathematical expressions as you type. Unlike a
standard calculator with buttons, you type full expressions such as
2 + 3 * 4, sin(pi/2), or sqrt(144) and see the result
update in real time.
The tool supports the standard arithmetic operators (+, -, *, /, ^ for power, % for modulo) and respects operator precedence and parentheses. A library of built-in functions covers the most common needs: trigonometric functions (sin, cos, tan), logarithms (log for base-10, ln for natural), rounding (ceil, floor, round), and helpers like sqrt, abs, and exp. Three mathematical constants are available by name: pi, e, and phi (the golden ratio).
All evaluation happens entirely in your browser using a safe
recursive-descent parser. The tool never calls JavaScript eval()
and never sends your input to any server. Your expressions stay on
your machine.
An expression history keeps the last ten evaluated results so you can quickly revisit or reuse previous calculations. Click any history entry to reload it. Quick-example buttons let you explore the supported syntax without typing.
If you need to convert between number systems, try the Number Base Converter. For CSS unit math, the px-rem Converter is purpose-built. Developers working with timestamps may also find the Timestamp Converter helpful alongside this evaluator.
How to Use
- Type a mathematical expression into the Expression input field (e.g.,
2 + 3 * 4). - The Result updates in real time as you type. No need to press a button.
- Press Enter to save the current expression to the History panel.
- Click the Copy button next to the result to copy it to your clipboard.
- Click the History icon to view and re-load your last 10 calculations.
- Use the Quick Examples buttons below the input to try common expressions like
sin(pi/2)orsqrt(144). - Press Ctrl+Shift+C to copy the result without clicking.
Popular Math Expression Guides
FAQ
What operators and functions are supported?
The evaluator supports +, -, *, /, ^ (power), and % (modulo) operators, plus parentheses for grouping. Built-in functions include sin, cos, tan, sqrt, abs, log (base 10), ln (natural log), ceil, floor, round, exp, pow, min, and max. Constants pi, e, and phi (golden ratio) are available by name.
Does the tool use eval()?
No. The evaluator uses a safe recursive-descent parser that tokenizes the input and builds an expression tree. JavaScript eval() is never called, so there is no risk of code injection.
What is the difference between log and ln?
log computes the base-10 logarithm (common logarithm), while ln computes the natural logarithm (base e). For example, log(1000) = 3 and ln(e) = 1.
How does operator precedence work?
The parser follows standard mathematical precedence: parentheses first, then exponentiation (^), then multiplication/division/modulo, then addition/subtraction. For example, 2 + 3 * 4 evaluates to 14, not 20.
Is my data safe?
Yes. All evaluation runs entirely in your browser. No data is sent to any server, no cookies are used, and your expressions are not logged anywhere. The expression history is stored only in component state and is cleared when you close the page.
Can I use the result of one calculation in the next?
You can click any entry in the History panel to reload a previous expression. While the tool does not support an 'ans' variable, you can copy a result and paste it into a new expression.
What happens with division by zero?
The evaluator detects division by zero and displays a clear error message instead of returning Infinity. Similarly, taking the square root of a negative number or the logarithm of zero will produce a descriptive error.
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