Free · No download · Full keyboard support

Casio Calculator Online

A fast, beautiful standard calculator with the key feel you trust. Type with your keyboard, get instant results, and switch to scientific mode anytime.

 
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Type with your keyboard · Enter =, Esc AC, Del

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How to use it

Three simple steps from open to answer.

Pick a mode

Stay on Standard for everyday math or jump to Scientific for advanced functions.

Enter your expression

Tap the keys or type directly. The display shows your full expression as you go.

Press equals

Hit = or Enter to compute. Use DEL to fix a typo or AC to start fresh.

Need sin, cos, logs and powers?

Switch to the full scientific calculator — same feel, more power.

Open Scientific Calculator

Understanding Your Calculator's Functions

A calculator looks simple, but knowing exactly what each key does turns it from a guessing game into a reliable tool. The standard CasioCalculator.Online keypad covers the four core arithmetic operations, plus a handful of helpers that make everyday math faster and more accurate. This guide walks through every function and shows real calculations you can try right now.

Addition, Subtraction, Multiplication and Division

These four operations are the foundation of every calculation you will ever make. Addition (+) combines values, subtraction (−) finds the difference, multiplication (×) scales a number, and division (÷) splits it into equal parts. The calculator follows the standard order of operations, known as PEMDAS, which means multiplication and division are resolved before addition and subtraction unless you use parentheses to change the order.

25.50 + 12.75 + 8.99=47.24Adding up a grocery receipt in one go.
100 − 67.35=32.65Working out the change from a 100 note.
2 + 3 × 4=14Multiplication runs first, so this is 2 + 12, not 20.

Parentheses: Controlling the Order

Parentheses are the most underused keys on any calculator, yet they prevent the majority of mistakes. Anything inside brackets is calculated first, which lets you force addition to happen before multiplication or division. If you are splitting a bill that includes tax, or averaging a set of numbers, parentheses keep everything grouped the way you intend.

100 ÷ (5 + 3)=12.5The bracket forces 5 + 3 = 8 first, then 100 ÷ 8.
(12 + 18 + 24) ÷ 3=18Averaging three numbers by grouping the sum.

The Percent Key

The percent (%) key is smarter than it looks. On its own it simply converts a number to its decimal form, so 50% becomes 0.5. But when you combine it with addition or subtraction, it behaves the way people actually expect: it calculates the percentage of the number that came before it. This is exactly how you add tax, apply a discount, or work out a tip without doing the math in two separate steps.

50 + 50%=7550 plus 50% of 50 (which is 25) gives 75.
85.40 × 15%=12.81A 15% tip on an 85.40 restaurant bill.
200 − 10%=180A 10% discount taken off a 200 price.

Clear, Delete and Correcting Mistakes

Two keys keep your input clean. AC (All Clear) wipes the entire expression and resets the display to zero, which is the fastest way to start a brand new calculation. DEL removes only the last character you typed, so if you fat-finger a digit you can fix it without losing the whole line. On a keyboard, the Escape key maps to AC and Backspace maps to DEL, which makes correcting typos almost instant.

Decimals and Precision

The decimal point (.) lets you enter exact values for money, measurements, and scientific quantities. The calculator carries results to high precision and only rounds for display, so chained calculations stay accurate. When you are working with currency, always include both decimal places to avoid confusing 0.05 with 5.

12.5 × 8.2=102.5Area of a room measured in feet.

Typing With Your Keyboard

Every function on this calculator responds to your keyboard, which is far faster than clicking once you get used to it. Type the number keys directly, use + − * / for the operators, the brackets keys for grouping, Enter or the equals key to compute, Backspace to delete, and Escape to clear everything. Because the calculator shows your full expression as you build it, you can read back exactly what you entered before pressing equals — no more wondering whether that last keypress registered.

Put together, these functions cover almost every everyday calculation: budgeting, shopping, cooking conversions, travel planning, and homework. When you need trigonometry, logarithms, powers or roots, the scientific calculator builds on this same foundation with a wider keypad. Try the examples above in the calculator at the top of the page to see each function in action.