Scientific Calculator Online Free
A full scientific calculator in your browser. Trig functions, logarithms, exponents, factorials, constants, angle mode toggle, and a history log. Works on any device instantly.
How this scientific calculator turns typed expressions into safe, evaluated results
Under the hood, this calculator does not implement its own recursive descent parser with a hand built grammar. Instead it takes a more pragmatic approach: it rewrites your expression, function names, constants, angle mode, factorials, into plain JavaScript syntax, then hands the rewritten string to a dynamically constructed Function that evaluates it. It is effectively a controlled, sandboxed eval, and understanding that rewrite step is the key to understanding exactly what this calculator can and cannot do.
Every keystroke and calculation happens in your browser. Nothing is transmitted anywhere, and your calculation history lives only in this page’s memory until you leave or clear it.
From typed expression to evaluated number
new Function(...) along with the trig wrapper functions and the Math object as explicit parameters, then invoked. This keeps the evaluation out of the page’s normal global scope, which is a narrower blast radius than a raw eval() call, though it is still fundamentally dynamic code execution rather than a parsed expression tree.
| Typed input | Rewritten to | Notes |
|---|---|---|
| sin(30) | __scSin__(30) | Degrees or radians per current mode |
| 2^10 | 2**10 | JS exponent operator |
| 5! | 120 | Factorial resolved before evaluation |
| log(100) | Math.log10(100) | Base-10, not natural log |
result.toPrecision(12) before display, then parses it back to trim trailing artifacts. This does not fix the underlying floating point representation, it just keeps the visible answer from exposing binary rounding error that has nothing to do with your actual calculation.Degree and radian toggle
Because the trig substitution happens through bound wrapper functions rather than being hardcoded, switching angle mode changes how every subsequent sin, cos, tan, and their inverses are interpreted without altering the expression text itself.
Calculation history
The last 50 evaluated expressions are kept in memory and clickable, letting you reload a previous result back into the input line to build on it, a lighter version of a graphing calculator’s answer memory.
- IEEE 754 is the floating point standard behind every JavaScript number and the reason results are rounded for display.
- MDN: the Function constructor documents the dynamic evaluation mechanism this calculator relies on.
- Order of operations is handled implicitly here by delegating to JavaScript’s own operator precedence rather than a custom-built parser.
Calculations this handles
Working trigonometry homework where you need to switch between degrees and radians quickly, checking an engineering calculation involving logarithms or exponents, verifying a quick physics formula with mixed operations without opening a full spreadsheet, and running exploratory arithmetic where keeping a visible history of prior steps matters more than a single throwaway answer. Anywhere you would normally reach for a handheld scientific calculator, this covers the same ground from a browser tab.
FAQ: Scientific Calculator Online Free
Yes, completely free. No account, no signup, and no payment required at any point.
Use DEG when your angles are in degrees, which is the default for most everyday problems and most high school level work. Use RAD when working in radians, which is standard in calculus, physics, and most programming environments. The mode affects all trig functions and their inverses.
Yes. Numbers, operators, parentheses, Enter for equals, Backspace to delete, and Escape to clear all work from your keyboard. This makes the calculator much faster for long calculations.
log is the logarithm base 10, also written log10. It asks how many times you need to multiply 10 by itself to get x. ln is the natural logarithm, base e. It uses the constant e (approximately 2.718) instead of 10 and appears frequently in calculus, physics, and finance.
Type the number then press the n! button. For example, type 5 then n! to get 120. Factorial is only defined for non-negative integers. The maximum supported value is 170 since 171! exceeds the maximum floating point number.
Yes. Click any entry in the history panel on the right to load that result back into the input. From there you can continue building a new expression with it.
From the blog
Number theory, lightly
Base systems, primes and the statistics people get wrong.
