How to Use This Free Online Calculator
Using the CalculatorAha basic calculator is simple. Click the number buttons to enter your first number, then press an operator — + (add), − (subtract), × (multiply) or ÷ (divide). Enter your second number and press = to instantly see your result.
You can chain calculations — after pressing equals, continue entering a new operator and number without clearing the display.
Special Buttons Explained
- AC (All Clear) — Resets everything to zero. Start a completely fresh calculation.
- +/− (Toggle Sign) — Switches the current number between positive and negative.
- % (Percent) — Converts the number to its percentage form. For example: 15 → 0.15.
- . (Decimal) — Adds a decimal point for numbers like 3.14 or 0.75.
- Backspace — Press on keyboard to remove the last digit entered.
Keyboard Shortcuts
You can operate the entire calculator from your keyboard:
- 0–9 — Enter digits
- + − * / — Arithmetic operators (use * for multiply, / for divide)
- Enter or = — Calculate the result
- Escape — Clear all
- Backspace — Delete last digit
Online Calculator – Simple Arithmetic for Everyone
A basic calculator is the most-searched calculator tool in the world. Whether you call it a calculator, calc, maths calculator or math calculator, this free online tool handles everyday arithmetic instantly — addition, subtraction, multiplication and division.
Used by students, teachers, professionals and anyone who needs a quick calculation — in the United States, United Kingdom, Canada, Australia, India, Nigeria, South Africa, Kenya, Ghana and every other country in the world. Works on mobile phones, tablets and desktop computers.
When to Use a Basic Calculator
- Splitting a bill at a restaurant
- Working out change from a payment
- Quick arithmetic during shopping
- Checking homework answers
- Basic business calculations
Calculator vs Scientific Calculator
A basic calculator handles the four core operations — add, subtract, multiply and divide. If you need trigonometry, logarithms, powers or scientific notation, use our free scientific calculator instead.
Frequently Asked Questions
How do I calculate a percentage of a number? +
To find 20% of 150: enter 150, press ×, enter 20, press %, then press =. The result is 30. Alternatively enter 150 × 0.20 = for the same result.
Can I use this calculator on my phone? +
Yes — CalculatorAha.com is fully mobile-optimised with large tap-friendly buttons. Works perfectly on iPhone, Android, and any tablet.
Does the calculator save my history? +
Yes! Every calculation appears in the History section below the calculator. Click any item to recall it. Press Clear to erase history.
What is the difference between basic and scientific calculator? +
A basic calculator handles the four core operations: addition, subtraction, multiplication and division. A scientific calculator adds trigonometric functions, logarithms, exponents and more. For everyday calculations a basic calculator is all you need.
Is this calculator free? +
Completely free — forever. No account, no sign-up, no subscription required.
