How to Use a Scientific Calculator

Quick Answer

A scientific calculator evaluates a whole expression at once, following the standard order of operations: parentheses first, then powers and roots, then multiplication and division, and finally addition and subtraction. So 2 + 3 x 4 is 14, not 20. This online scientific calculator also works as a trig calculator and a log calculator, handling trigonometry, logarithms, exponents, roots, factorials, and constants like pi and e, and it lets you choose whether angles are in degrees or radians. Type or tap an expression and read the result instantly.

A Scientific Calculator vs a Basic Calculator

A basic online calculator handles one operation at a time and ignores precedence, so pressing 2 + 3 x 4 gives 20. A scientific calculator vs a basic calculator differs in two ways: it reads a full expression with correct order of operations, and it adds functions a basic model lacks, such as trig, logs, and exponents. That is why students reach for a sci calc or student calculator once problems involve angles, powers, or nested parentheses.

How the Calculator Works: Order of Operations

The calculator resolves precedence for you, so you can write an expression the way you would on paper. The rules, from first to last, are: anything inside parentheses, then powers and roots, then multiplication, division, and modulo, and last of all addition and subtraction. Operators of the same level are read left to right, except powers, which are read right to left, so 2^3^2 means 2^(3^2). When in doubt, add parentheses: they make your intent explicit and never change the wrong answer into a right one by accident.

Degrees Versus Radians

Trigonometry functions need to know what unit your angle is in. In degrees, a full turn is 360 and sin(30) is 0.5. In radians, a full turn is 2 pi and the number 30 is a much larger angle, so sin(30) gives a completely different value. Use the DEG and RAD buttons to switch. Most school and exam questions are in degrees, so if a trig answer looks wrong, the first thing to check is the mode. Inverse functions such as asin return their answer in the unit you have selected.

Functions And Constants

The keypad covers the functions you meet through school and early university: sine, cosine, and tangent with their inverses; the natural logarithm ln and the base 10 logarithm log; the exponential e^x; square root, cube root, and absolute value; floor, ceiling, and round; powers with the x^y key; and factorial with x!. The constants pi and e are one tap away, and Ans drops your previous answer into a new calculation so you can build on it. Functions and parentheses nest freely, so sqrt(ln(100)) is perfectly valid.

Memory Keys

Memory is a small scratchpad for a single number. MS stores the current value, MR recalls it into your expression, and MC clears it. M+ adds the current value to memory and M- subtracts it, which is ideal for keeping a running total while you work through parts of a problem. A small M appears above the keypad whenever memory holds a value, so you always know it is there. Your history and memory stay on your device and are restored when you come back.

Worked Examples

For example, here is how a few common expressions evaluate:

• (2 + 3) x 4 = 20. The parentheses force the addition first; without them, 2 + 3 x 4 is 14.
• sin(30) = 0.5 in degrees. Switch to radians and the same keys give about minus 0.988, because 30 radians is a different angle. This is the degrees radians distinction in action.
• 2^10 = 1024. This is how to raise a number to a power: use the x^y key, or type the caret directly on your keyboard.
• 5! = 120. The factorial multiplies 5 x 4 x 3 x 2 x 1.
• 2 pi = 6.2832. Writing a number directly before pi is understood as multiplication.

Common Mistakes

• Expecting addition to happen before multiplication. It does not: use parentheses when you need to.
• Leaving the calculator in radians for a degrees question, or the reverse.
• Forgetting a closing parenthesis in a nested expression, which the calculator will flag.
• Reading 1/2 pi as 1/(2 pi). It is read left to right as (1/2) x pi, so add parentheses to be sure.

Try It Yourself

Work an expression from your homework, switch between degrees and radians to see how trig answers change, and use Ans to chain one result into the next. Everything runs in your browser, so nothing you calculate leaves your device.