A scientific calculator does far more than a basic one, but the extra buttons hide behind a simple pattern: main arithmetic in the middle, functions like powers and roots on the sides, and utility keys such as memory and angle mode around the edges. Once you know what a handful of buttons do, everything else falls into place.
Key Takeaways
- Arithmetic works with standard precedence, so
12 + 7 × 3is33, not57.%is a short-cut:200 × 56%=112,200 + 10%=220.√and∛invert squaring and cubing; trig needs the right angle mode (DEG or RAD).- Memory keys (
M+,MR,MS,MC) store one value for later.
Step 1: Learn the layout of the keypad
Almost every scientific calculator groups its keys the same way. The core grid holds the digits, the decimal point, and the four operators. Around it sit three other groups: function keys such as √ and sin(; a memory row with MC, MR, MS, M+, M−; and mode toggles for angle (DEG/RAD) and display format (SCI). On The Scientific Calculator, you type into a live expression box, so the full expression is visible and editable before you press =.
The main arithmetic keys
The keys +, −, ×, and ÷ work exactly as you expect, but the calculator applies the standard order of operations: powers come before multiplication and division, which come before addition and subtraction. Put differently, the calculator follows the math, not the order you type. If you want a different grouping, you add parentheses, for example (12 + 7) × 3.
The function keys
Function buttons insert their name plus an opening parenthesis, so sin( is typed before the angle. The key ones for beginners are √ for square root, ∛ for cube root, and ^ for powers such as 2^10. Logarithms live here too: log(…) is base 10 and ln(…) is natural (base e). A full list of what each button inserts is in the calculator function reference.
The memory and mode keys
The memory row keeps one number stashed in the background: MS (memory store) saves the current answer, MR recalls it, M+ / M− add or subtract from it, and MC clears it. The mode keys are separate toggles: DEG/RAD changes how angles are measured, and SCI switches the display to scientific notation. Both are covered in their own sections below. If you prefer the physical keyboard to the on-screen keypad, the keyboard shortcuts guide lists every key that maps to a calculator action.
Step 2: Do basic arithmetic with correct precedence
Enter 12 + 7 × 3 and press =. You will get 33, not 57, because multiplication is evaluated before addition:
- Multiplication runs first:
7 × 3 = 21. - Addition finishes the job:
12 + 21 = 33.
Worked example 1: order of operations. Type 12 + 7 × 3 → = 33. If you instead wanted the sum first, enter (12 + 7) × 3 → = 57. Parentheses override the default grouping.
Step 3: Use the % key for percentages
The percent key is a click-based shortcut for “divide by 100”. Typed next to ×, ÷, +, or −, it applies the percentage to the other number in the expression.
Worked example 2: percentages. 200 × 56% → = 112 is 56% of 200. 200 + 10% → = 220 adds 10% of the base to 200. 200 − 10% → = 180 subtracts it. Notice that in the add and subtract forms the 10% is taken from the 200 itself, which is the behavior most everyday calculators use.
Step 4: Use powers and roots
The ^ key raises a number to a power, and √ / ∛ undo that in the square and cube cases.
Worked example 3: powers and roots. 2^10 → = 1024 (ten copies of 2 multiplied together). √(144) → = 12 because 12 × 12 = 144. ∛(512) → = 8 because 8³ = 512. Roots that are not whole numbers stay exact as far as the engine can represent them, so √(2) displays as 1.41421356237, a 12-significant-digit approximation of the irrational value. The relationship between roots and powers is covered in the exponents explained post, and the calculator’s own expression box makes squared and cubed checks trivial to verify along the way.
Step 5: Do trigonometry in the right angle mode
Sine, cosine, and tangent read an angle and return a ratio. The angle can be measured in degrees or radians, and the DEG/RAD toggle decides which. The calculator defaults to DEG, which is what you want for most everyday work; the degrees vs radians guide shows when each mode is appropriate.
Worked example 4: trigonometry. In DEG mode: sin(30) → = 0.5, cos(60) → = 0.5, and tan(45) → = 1. These are the classic exact values you should be able to reproduce on any scientific calculator in degree mode. If you switch to RAD and see sin(30) return -0.988031624093, that is not a bug, the angle is now interpreted as 30 radians.
Step 6: Use log for powers-of-ten and ln for natural logs
log(…) answers “10 raised to what power gives this number?”, and ln(…) answers the same question for the constant e (about 2.71828). The site’s log calculators can check your work on either base.
Worked example 5: logarithms. log(1000) → = 3, because 10³ = 1000. ln(e) → = 1, because the first power of e is e itself. As a sanity check on your entries, log(100) → = 2 and ln(100) → = 4.60517018599.
Step 7: Stash a value with the memory keys
Memory is for when an intermediate answer reappears later in a calculation. MS stores the current result, MR pastes it back in, and M+ adds the current result to whatever is stored.
Worked example 6: memory. Compute 3 × 4 → = 12, then press MS to store 12. Clear the box and enter 25 − 12 → = 13. More conveniently, press MR after the 25 − and let the stored 12 come back automatically: same answer, fewer keystrokes.
Step 8: Read results in SCI (scientific notation)
SCI mode reformats the display for very large or very small numbers as a mantissa times a power of ten, written like 1.23456789e+8. Pressing SCI shows 123456789 as 1.23456789e+8 even though the value is unchanged. This is the same notation used across science, and the scientific notation calculator converts between the forms in either direction. If an answer suddenly looks like 3e-7, you are reading 3 × 10⁻⁷, not an error.
Frequently asked questions
Why does 12 + 7 × 3 not give 57?
Because powers, multiplication, and division run before addition and subtraction. The calculator evaluates 12 + 7 × 3 as 12 + 21. To force the sum first, wrap it in parentheses: (12 + 7) × 3.
What is the difference between DEG and RAD?
They are two ways to measure angles. A full turn is 360 degrees or 2π radians, so sin(30) in DEG equals sin(π ÷ 6) in RAD. Use DEG for everyday angles and RAD for calculus and most physics work.
What does the % key actually do?
After × or ÷ it just divides by 100, so 200 × 56% = 112. After + or − it takes that percentage of the base number, so 200 + 10% = 220 means add 10% of 200.
How do I use the memory keys?
Press =, then MS to store the answer. MR recalls it at the caret, M+ and M− adjust the stored value, and MC clears it. The stored value survives until you change it or switch your browser tab.