How to use this calculator
- Type or click numbers and operators to build your expression.
- Use the function keys — sin, cos, log, √ and more — as needed.
- Press = to evaluate; the result respects standard order of operations.
What your result means
The result follows standard order of operations, not the order you typed things in: brackets first, then powers and roots, then multiplication and division, then addition and subtraction. So 2 + 3 × 4 is 14, not 20. If you meant the other one, the brackets are not optional.
Two other things shape the number you see. Trigonometric functions use whichever angle mode is showing — DEG or RAD above the keys — and the same keystrokes give completely different answers in each. And results are computed in binary floating point, the same arithmetic every computer uses, so a long chain of operations can leave a trailing 0.0000000001 where you expected a round number. That is a display artefact of the format, not an error in the maths.
Why this one is different
Whether angles are being read as degrees or radians is stated on screen and switched with one button, which is where most trigonometry answers quietly go wrong. The expression stays visible as you build it, so a missing bracket is caught before the equals key rather than after it.
The setting that trips everyone up
The single most common calculator mistake isn't a typo — it's the angle mode. sin(90) is 1 in degrees but roughly 0.894 in radians. Same keys, completely different answer.
This calculator shows DEG or RAD right above the keys — tap it to switch. Everyday geometry usually wants degrees; calculus and programming usually want radians.
Worked example
Three expressions that catch people out:
sin(30) in DEG = 0.5
sin(30) in RAD = −0.988
0.1 + 0.2 = 0.30000000000000004
The first is order of operations — multiplication binds tighter than addition, so brackets are the only way to force (2 + 3) × 4. The second pair is the angle-mode trap: same keystrokes, unrelated answers. The third is binary floating point, the arithmetic every computer uses — a tenth cannot be written exactly in binary any more than a third can be written exactly in decimal, so tiny residues appear. None of these is a fault in the calculator.
Frequently asked questions
How do I calculate a power?＋
Use the ^ key: type 2 ^ 10 then = to get 1024. Use x² for a quick square.
Does it work offline?＋
Yes — once the page loads it runs entirely in your browser, so it keeps working without a connection.
Does it use degrees or radians?＋
There is a mode switch, and it matters: sin 30 is 0.5 in degrees but -0.988 in radians. Trigonometry homework is usually in degrees; calculus and programming almost always in radians.
What is the difference between log and ln?＋
Log is base 10, ln is base e, approximately 2.718. Scientific and financial formulas usually mean ln when they write log without a base, which is a frequent source of error.
How does the memory work?＋
M+ adds the displayed value to memory, MR recalls it and MC clears it. It is the quickest way to hold a subtotal while you calculate another part of a problem.
Why do I get a small error instead of an exact zero?＋
Because the calculator works in binary floating point, where some decimal values cannot be represented exactly. A result like 1e-16 instead of 0 is that rounding, not a fault.
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Assumptions & limitations
The arithmetic is standard, with the usual limits of computer arithmetic:
- Calculations use binary floating point, so some decimal values cannot be represented exactly and results may show a tiny residual error.
- Trigonometric functions depend on the degrees or radians mode you have selected; the same input gives a different answer in each.
- Very large and very small magnitudes are displayed in exponential notation and carry about 15 significant digits.
- Log is base 10 and ln is base e. Sources that write log without a base often mean the natural logarithm.
Operator precedence is why the answer surprises you
This calculator evaluates expressions in the standard order: brackets, then exponents, then multiplication and division left to right, then addition and subtraction left to right. So 2 + 3 × 4 is 14, not 20, and 2 ^ 3 ^ 2 is 512 because exponentiation associates right to left. Simple four-function calculators often evaluate strictly in the order keys are pressed and will give 20 for the first of those — which is not a bug in either device, but a difference in convention worth knowing before trusting a result.
Degrees, radians and the mode that catches everyone
Trigonometric functions need to know which angle unit you mean. sin(30) is 0.5 in degrees and −0.988 in radians, and nothing about the answer signals which mode produced it. Radians are the default in most programming languages and in calculus; degrees are usual in surveying, navigation and school geometry. Check the mode before the first trig calculation of a session rather than after an answer looks odd, and remember that inverse functions return in whichever unit the mode is set to.