Scientific Calculator
This free online scientific calculator handles trigonometry (sin, cos, tan and their inverses), logarithms, powers, roots, factorial, and the constants pi and e, alongside the everyday four-function math and memory this site's Basic Calculator offers. Type with the on-screen buttons or your keyboard. Nothing you enter is sent anywhere or stored.
How to Use It
- Type a number using the keypad or your keyboard.
- Press a function key (sin, log, √, and so on) to apply it immediately, or an operator (+, −, ×, ÷, xʸ) to combine it with a second number.
- Press = for the result.
- Switch DEG/RAD before using sin, cos, tan, or their inverses, and use M+, M−, MR, MC to store and recall a value in memory.
How It Works
Like this site's Basic Calculator, this calculator evaluates operations immediately in the order you press them, rather than parsing a full expression with parentheses and algebraic precedence. The scientific function keys (sin, log, √, and the rest) work differently from +, −, ×, and ÷ though: they apply immediately to whatever number is currently on the display, the same "function key acts now" behavior a physical scientific calculator has, instead of waiting for a second number the way an operator does.
The DEG/RAD toggle controls how sin, cos, and tan interpret the number you give them, and how their inverses report their answer back. A worked example in the default DEG mode: entering 30 and pressing sin gives 0.5, since the sine of 30 degrees is exactly one half. Switch to RAD first and that same 30 is instead treated as 30 radians, giving a very different result, so it's worth checking the toggle before a trig calculation.
Powers use the xʸ key: entering 2, pressing xʸ, entering 10, then pressing = gives 1024 (2 to the 10th power). Roots, reciprocals, squares, and factorial (x!) all apply immediately like the other function keys, for example entering 16 and pressing √ gives 4.
An input outside a function's valid range, like a negative number into √, or a number outside -1 to 1 into sin⁻¹, shows Error rather than a made up answer, the same way dividing by zero does. Everything runs client-side in your browser. No numbers you enter are sent anywhere or stored.
Frequently Asked Questions
Why is there no parentheses key, or algebraic order of operations?
This calculator evaluates key presses immediately as you enter them, the same chain model this site's Basic Calculator uses, rather than parsing a full expression with parentheses and precedence. 2 + 3 × 4 evaluates as (2 + 3) × 4 = 20, not 14, since the + is calculated the moment × is pressed. Older handheld scientific calculators work exactly this way too, so this isn't a shortcut, it's a real, common calculator design.
What does the DEG/RAD toggle control?
It sets whether sin, cos, and tan treat the number you enter as degrees or radians, and whether sin⁻¹, cos⁻¹, and tan⁻¹ report their answer in degrees or radians. It defaults to DEG, the more familiar unit for most everyday calculations, and stays on whichever mode you pick even after you press AC, since it is a setting, not part of any one calculation.
Why do sin⁻¹ and cos⁻¹ sometimes show Error?
Sine and cosine only ever produce a value between -1 and 1, so their inverses are mathematically undefined for anything outside that range. Entering, for example, 2 and pressing sin⁻¹ has no real answer, so it shows Error rather than a made up number.
Why do log, ln, and √ sometimes show Error?
Log and ln are undefined for zero or a negative number, and square root is undefined for a negative number (within real numbers, which is what this calculator works with). Entering a value outside each function's valid range shows Error instead of a nonsensical result.
What counts as valid input for x! (factorial)?
A whole, non-negative number: 0, 1, 2, and up. Factorial is only defined for non-negative integers here, so a negative number or one with a decimal point shows Error. A large enough factorial (past a couple hundred) also shows Error once the result grows too large for the display, the same overflow rule every other calculation on this page follows.
What happens when I press π or e?
They insert the constant's value straight onto the display, ready to use in a calculation, rather than computing anything themselves. Pressing × then π after a number, for example, multiplies that number by pi.
How is this different from the Basic Calculator?
This one adds trigonometric functions (sin, cos, tan and their inverses), logarithms, powers, roots, factorial, and the constants pi and e, on top of everything the Basic Calculator already does. If you only need everyday arithmetic and percentages, the Basic Calculator has a simpler keypad with the same chain calculation model.
What happens if I divide by zero, or use xʸ with an undefined result?
Both show a clear Error rather than a nonsensical or crashed result, the same as dividing by zero on the Basic Calculator. An undefined power, like a negative number raised to a fractional exponent, is treated the same way. Enter a new number afterward to start a fresh calculation.