Scientific Calculator Online
Full scientific calculator with trigonometry, logarithms, powers, factorials, and mathematical constants. Degree and radian modes. Runs entirely in your browser — no app, no download.
⏱ 6 min read · Complete guide below
How to Use the Scientific Calculator
- 1Set DEG or RAD mode using the toggle in the top-left before entering trig functions.
- 2Enter numbers and operations — use scientific function buttons (sin, cos, log, etc.) which automatically open a parenthesis.
- 3Close parentheses with ), then press = to evaluate.
- 4Use DEL to backspace and AC to clear everything.
Functions Reference
Trig: sin, cos, tan (and their inverses sin⁻¹, cos⁻¹, tan⁻¹) — respects DEG/RAD mode. Logarithms: log (base 10), ln (natural log). Powers: xʸ (any power), x² (square), √ (square root), 1/x (reciprocal). Constants: π (3.14159…), e (2.71828…). Other: n! (factorial), abs (absolute value), % (percent).
Degrees vs Radians — The Number-One Source of Errors
If a trigonometry answer looks wrong, the culprit is almost always the angle mode. Calculators can interpret an angle in two units: degrees, where a full circle is 360, and radians, where a full circle is 2π (about 6.283). They are not interchangeable — sin(90) equals 1 in degree mode but about 0.894 in radian mode, because 90 radians is a completely different angle. As a rule of thumb, geometry, surveying, and most everyday problems use degrees, while calculus and physics generally use radians. Always glance at the DEG/RAD indicator before entering a trig function, and switch it with the toggle if needed; this single habit prevents the most common mistake people make on a scientific calculator.
Order of Operations and Parentheses
This calculator evaluates full expressions rather than one operation at a time, which means it respects the standard order of operations — often remembered as PEMDAS or BODMAS: parentheses first, then exponents, then multiplication and division, and finally addition and subtraction. That is powerful, but it also means you must be explicit about what you intend. To divide a sum, wrap it: (3 + 5) / 2 gives 4, whereas 3 + 5 / 2 gives 5.5. When in doubt, add parentheses — they never change a correct expression and they routinely rescue an ambiguous one. Every opening parenthesis needs a matching close, so a good habit is to add both at once and fill in between them.
Getting the Most From the Functions
Beyond the basics, a few features repay learning. The logarithm buttons split into log (base 10, used for pH, decibels, and the Richter scale) and ln (natural log, base e, used in growth, decay, and calculus). The power button raises to any exponent, and you can use it for roots too by entering a fractional power — a cube root is simply raising to the ⅓ power. Factorials(n!) count arrangements and appear throughout probability and combinatorics, though they grow so fast that anything past 170! exceeds the calculator's numeric range. And the built-in constants π and e save you from typing long decimals and keep your results as precise as possible.
Calculator Tips
Always check DEG vs RAD
The most common error with trig functions is the wrong angle mode. sin(90) in DEG = 1. sin(90) in RAD ≈ 0.894.
Use parentheses for clarity
Complex expressions like sin(30) + cos(45) × 2 should use explicit parentheses to ensure operations evaluate in the right order.
Chaining functions
You can nest functions: log( sqrt( 100 ) ) = log(10) = 1. Just make sure every opening parenthesis has a matching close.
Percent shortcut
Press % after a number to divide it by 100 inline. For example: 200 × 15 % = 30 (15% of 200).
Large factorials
Factorials grow extremely fast. 20! ≈ 2.4 × 10¹⁸. Anything above 170! overflows to Infinity on JavaScript's 64-bit float.
1/x for reciprocals
Press 1/x to insert (1/ before your number. Close the parenthesis and press = to get the reciprocal of any expression.
Frequently Asked Questions
How do I switch between degrees and radians?
Press the DEG/RAD button in the top-left of the calculator to toggle between degree mode and radian mode. The current mode is shown in the display. When in DEG mode, trig functions accept and return values in degrees (e.g., sin(90) = 1). In RAD mode, they use radians (e.g., sin(π/2) = 1).
How do I enter trigonometric functions?
Press sin, cos, or tan — the calculator opens the function with a parenthesis. Enter your angle and close the parenthesis manually with the ) button, then press =. Example: sin( 30 ) = 0.5 in degree mode.
What is the difference between log and ln?
log computes the base-10 logarithm (common logarithm). ln computes the natural logarithm (base e ≈ 2.71828). For example: log(100) = 2, ln(e) = 1. Use log for pH calculations and decibels; use ln for exponential growth and calculus.
How do I calculate powers and exponents?
Use xʸ to raise a number to any power (e.g., 2 xʸ 8 = 256). x² appends ^2 for squaring. For cube roots or other roots, use xʸ with a fraction exponent: 8 xʸ (1/3) = 2.
How does factorial (n!) work?
Press n! after entering a positive integer to compute its factorial. For example: 5 n! = 120 (5 × 4 × 3 × 2 × 1). Factorials grow very quickly — the calculator supports up to 170! before overflowing to Infinity.
Is the data I calculate stored anywhere?
No. All calculations run entirely in your browser in JavaScript. Nothing is transmitted to a server, nothing is stored.
Can I use π and e as constants?
Yes. Press π to insert the value of pi (3.14159…) and e to insert Euler's number (2.71828…). They can be used in any expression, for example: 2 × π = 6.28318…
Does the calculator follow order of operations (PEMDAS)?
Yes. It evaluates the whole expression using the standard order of operations: parentheses first, then exponents, then multiplication and division, and finally addition and subtraction. This means 3 + 5 / 2 gives 5.5, not 4. If you want a sum evaluated before a division, wrap it in parentheses: (3 + 5) / 2 gives 4. When an expression is complex, adding parentheses is the safest way to get the result you intend.
How do I calculate a root other than a square root?
Use the power button with a fractional exponent. Any root can be written as a power: a cube root is the same as raising to the 1/3 power, a fourth root is the 1/4 power, and so on. For example, to find the cube root of 8, enter 8 raised to (1/3), which gives 2. The dedicated square-root button is just a shortcut for the ½ power.
Can I use the keyboard instead of clicking buttons?
In most browsers you can type numbers and the basic operators (+, −, *, /) directly, use parentheses, and press Enter to evaluate. The on-screen buttons are always available for the scientific functions like sin, log, and factorial. Using the keyboard for digits and operators while clicking the function buttons is often the fastest way to enter a long expression.
Is this scientific calculator suitable for exams or homework?
It covers the standard scientific functions used in high-school and college math, physics, and chemistry — trigonometry, logarithms, powers, roots, factorials, and the constants π and e — so it is well suited to homework and study. For actual exams, always use the calculator model your institution permits; many exams require a specific approved physical calculator and do not allow web tools. Use this as a practice and homework aid rather than an exam substitute.