How to use a calculator: a step-by-step guide
Last reviewed on 2 October 2026.
A calculator works the way most people expect: type a calculation, press equals, read the answer. This guide covers the basics for anyone new to a calculator, how to type the things that are not obvious — brackets, powers, roots, percentages, negative numbers — and then the details of the claculator.com online calculator: keyboard shortcuts, the DEG and RAD modes, the scientific panel, and history. If you only have a minute, read the first two sections.
The basics in five steps
- Clear the calculator. Press
AC(all clear) so nothing from a previous calculation is left over. On the keyboard, press Esc. - Type the first number. Tap the digits, or type them on your keyboard. Use
.for the decimal point. - Choose an operation.
+add,−subtract,×multiply,÷divide. On a computer keyboard these are + - * /. - Type the next number, and keep going for longer calculations such as
12 × 4 + 7. A live preview of the answer appears as you type. - Press
=(or Enter). The answer appears in large digits, and the calculation is saved to history. Typing a new number starts a fresh calculation; typing an operator continues from the answer.
Made a typo? ⌫ (or Backspace) removes the last character, so you do not have to start again.
How to type common calculations
Everything below works on this calculator, either with the on-screen keys or the keyboard. Most scientific calculators accept the same input with slightly different key labels.
| To calculate | Type | Result |
|---|---|---|
| Brackets (parentheses) | (3 + 5) × 2 | 16 |
| A square, 7² | 7^2 | 49 |
| Any power, 2¹⁰ | 2^10 | 1,024 |
| Square root of 144 | √(144) | 12 |
| Cube root of 27 | ∛(27) | 3 |
| Fifth root of 32 | 32^(1/5) | 2 |
| A negative number | -5 × 3 | −15 |
| A fraction, ¾ of 60 | 3/4 × 60 | 45 |
| 15% of 80 | 80 × 15% | 12 |
| 80 plus 15% | 80 × (1 + 15%) | 92 |
| Area of a circle, r = 3 | π × 3^2 | 28.2743… |
| Sine of 30° | sin(30) in DEG mode | 0.5 |
| Natural log of 10 | ln(10) | 2.302585… |
| Factorial, 5! | 5! | 120 |
| Scientific notation, 3 × 10⁸ | 3 × 10^8 | 300,000,000 |
How to use brackets
Brackets — also called parentheses — tell the calculator which part to work out first. Without them the calculator follows the order of operations, so 2 + 3 × 4 is 14, while (2 + 3) × 4 is 20.
- On the scientific panel there are separate
(and)keys. - On the standard keypad, the single
( )key does both: it opens a bracket, and once you have typed a number inside an open bracket it closes it. - On a keyboard, type ( and ) directly (Shift + 9 and Shift + 0 on most layouts).
- Forgot to close one? When you press equals, missing closing brackets at the end are added automatically, so
√(16still returns 4. - A number written right next to a bracket is multiplied:
2(3 + 1)is read as2 × (3 + 1)= 8.
Keyboard shortcuts
Every basic action has a keyboard equivalent so you can keep your hands on the keys.
| Key | What it does |
|---|---|
| 0–9 | Insert a digit |
| . or , | Decimal point |
| + - * / | Add, subtract, multiply, divide |
| % | Percent (see the % key explained) |
| ^ | Power (2^10 = 1024) |
| ! | Factorial (5! = 120) |
| ( ) | Brackets for grouping |
| Enter or = | Calculate |
| Backspace | Remove the last character or function name |
| Esc or Delete | Clear everything (AC) |
Functions like sin, log, and √ do not have single-key shortcuts. Tap them on the SCI panel and they are inserted as sin(, log(, or √(, ready for the number. If you tap a function straight after pressing equals, it is applied to the previous answer.
The display and the live preview
The display has two lines. The top line shows the expression you are building, with multiplication shown as ×, division as ÷, and π and √ in their familiar shapes. The bottom line shows the live result. As long as the expression is well formed, the result updates while you type — useful for catching mistakes before pressing equals.
If the expression is incomplete (a trailing operator, a function with nothing inside yet), the live preview keeps the last valid value rather than blanking out. Very large and very small answers are shown in scientific notation: 1.5E+20 means 1.5 × 10²⁰ and 2E-9 means 2 × 10⁻⁹. You can keep calculating with them as normal.
DEG and RAD
Two pills sit above the display. DEG means trigonometric functions interpret their argument as degrees; RAD means radians. The mode applies to sin, cos, tan, and the inverse trig keys. It does not change anything else. Picking the wrong mode is the single most common reason a result looks wrong; if you are not sure which one you need, see degrees vs radians.
In DEG mode, angles that sit exactly on an axis give exact answers: sin(180) is 0 and cos(90) is 0, and tan(90) shows "Undefined" because the tangent of a right angle does not exist.
The SCI panel
The third pill toggles the scientific panel. On wider screens it is open by default; on phones it starts closed to keep the standard keypad larger. Inside the panel:
- Trigonometry:
sin,cos,tanand their inversessin⁻¹,cos⁻¹,tan⁻¹. - Logarithms:
logfor base 10,lnfor natural log. See log vs ln if you are not sure which to use. - Exponentials:
10ˣ,eˣ, andxʸfor arbitrary powers. - Roots:
√for square root and∛for cube root. Higher roots can be written as fractional powers, for example32^(1/5). - Other: factorial
x!, absolute value|x|, reciprocal1/x, and the constants π and e.
History
Every successful calculation is added to the history list at the bottom of the calculator, newest first. Click any entry and its result becomes the starting point for a new calculation; a fresh number replaces it, an operator continues from it. The list keeps the most recent fifty entries and resets when you reload the page.
How the percent and power keys behave
The percent key on this calculator is a literal divide-by-one-hundred. Typing 200 + 10% is the same as 200 + 0.1, which equals 200.1. Some physical calculators interpret the same keystrokes as "10% of 200, then add", giving 220. Neither is wrong, but they are different. The full breakdown is in using the % key.
The power key uses standard right-associativity: 2^3^2 means 2^(3^2) = 512, not (2^3)^2 = 64. Powers also bind tighter than a leading minus sign, so -3^2 is −9; type (-3)^2 to get 9.
Using a physical calculator
Handheld calculators follow the same ideas with a few differences worth knowing:
- Basic four-function calculators usually work out each step as soon as you press the next operator, so
2 + 3 × 4gives 20. Scientific calculators, phone calculators in scientific mode, and this site follow the order of operations and give 14. - The SHIFT or 2nd key unlocks the function printed above a key, often in a different colour. On many scientific models, %, x⁻¹, the inverse trig functions and 10ˣ live there.
- The (−) key on scientific calculators types a negative sign, which is different from the subtraction key. Use it for numbers such as −5.
- Ans recalls the previous answer, like continuing from a result here.
- The mode indicator — a small D, R or G on the display — shows degrees, radians or gradians. Check it before any trigonometry.
Common mistakes
- Wrong trig mode. If
sin(30)gives roughly-0.988, you are in RAD when you wanted DEG. - Missing brackets.
1/2+3is 3.5, not 0.2. Group the denominator:1/(2+3). - Negative bases under fractional powers.
(-8)^(1/3)returns an error, because a negative number raised to a fractional power is not a real number in general. Use the dedicated∛key, which returns the real cube root −2. - Implicit multiplication next to division.
2πand2(3+1)work, but8/2(2+2)is read as8/2 × (2+2)= 16. If you mean 8 divided by the whole of2(2+2), add brackets:8/(2(2+2)). - Comma versus dot. Both , and . insert a decimal point. Thousand separators in the result are display-only; you cannot type them.
Frequently asked questions
How do I type brackets on a calculator?
Use the ( and ) keys, or the single ( ) key on the standard keypad of this calculator, which opens a bracket or closes an open one. On a computer keyboard, type ( and ) directly.
Does this calculator follow BODMAS / PEMDAS?
Yes. Brackets first, then powers, then multiplication and division from left to right, then addition and subtraction from left to right. 2 + 3 × 4 returns 14.
How do I use the % key?
Here, % divides the number before it by 100. For 15% of 80, type 80 × 15%. To add 15%, type 80 × (1 + 15%). Some office calculators treat 80 + 15% differently, so the multiplying form is the safest.
How do I enter a negative number?
Type the minus sign before the number, for example -5 × 3. For a negative number raised to a power, use brackets: (-3)^2 = 9, while -3^2 = -9.
How do I calculate a square root?
Open the SCI panel and press √, then type the number: √(144) = 12. For other roots use a fractional power, such as 32^(1/5) for the fifth root.
What does E mean in an answer?
E means "times ten to the power of". 1.5E+20 is 1.5 × 10²⁰ and 2E-9 is 2 × 10⁻⁹. Very large and very small answers are shown this way.
Can I use the calculator with my keyboard?
Yes. Digits, + - * / ^ % ! and brackets type directly, Enter calculates, Backspace deletes the last character and Esc clears everything.
Accessibility notes
The display uses ARIA live regions, so screen readers announce the live preview and the final result. Every button is keyboard focusable. The colour scheme follows your operating system preference and switches between dark and light automatically. If anything blocks you from using the calculator with assistive technology, please write to [email protected].