Online Calculator (Basic & Scientific)
A full basic and scientific calculator in your browser: trig, logs, powers, roots, constants, and keyboard support.
How to Use Online Calculator (Basic & Scientific)
Click the mode switch to toggle between Basic and Scientific panels.
Type with the buttons or your physical keyboard; Enter evaluates, Escape clears, Backspace deletes.
Use DEG/RAD to set the angle mode for trig functions in Scientific mode.
Review or reuse previous results from the expression history panel.
About Online Calculator (Basic & Scientific)
A dependable calculator that is always one keystroke away โ no app download, no ads covering the buttons. Basic mode covers everyday arithmetic with percent and sign toggle; Scientific mode adds trigonometric functions (with degree/radian switching), natural and base-10 logarithms, exponentials, powers, roots, factorials, constants (ฯ and e), and memory (MS/MR/M+/MC). Expressions are evaluated by a local recursive-descent parser โ not the risky eval() shortcut โ so operator precedence, parentheses, and unary minus all behave exactly as they should, with a scrollable expression history you can reuse.
Frequently Asked Questions
Does it respect operator precedence (PEMDAS/BODMAS)?
Yes. A real expression parser evaluates parentheses, then exponents, then multiplication/division, then addition/subtraction โ with correct left-associativity and unary minus handling, matching what you expect from a physical scientific calculator.
How does it avoid the dangerous eval() approach most web calculators use?
Input is tokenized and evaluated by a small recursive-descent parser built for arithmetic only. Arbitrary code can never execute because arbitrary input is never evaluated as code.
Does it work offline?
Yes โ all math runs locally with the browser's built-in floating-point engine. The site's service worker even caches the page for offline use.
Why do results like 0.1 + 0.2 show 0.30000000000000004?
That is standard IEEE-754 floating-point behavior (the same happens in Excel, Python, and physical calculators with internal precision limits). The display smartly rounds harmless float noise at the 12th significant digit while keeping full precision internally.
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