Basic Calculator

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Includes your inputs and results for this calculation, plus any additional calculations you've compared.

How This Online Calculator Works

A basic calculator adds, subtracts, multiplies, and divides — the everyday arithmetic most people reach for a calculator for. Type an expression using the field or the button pad below, including parentheses, and get the result instantly.

This shares its expression field with Scientific Calculator, so it correctly follows the standard order of operations for a full expression, not just one operation at a time — 3 + 4 * 2 correctly evaluates to 11 (not 14), since multiplication happens before addition. Tap “Scientific” in the toggle above the calculator any time you need trig functions, logarithms, exponents, or factorials — your choice is remembered for next time.

The Formula

Expressions are evaluated in this order, from first to last:

  1. Parentheses — anything inside ( ) is evaluated first.
  2. Multiplication and division (*, /), left-to-right.
  3. Addition and subtraction (+, -), left-to-right.

Key Factors to Consider

  • Order of operations always applies, even when it isn’t what you’d expect from typing left to right. 10 - 2 * 3 evaluates to 4, not 24, because multiplication is always performed before subtraction regardless of the order the numbers were typed in — use parentheses whenever you want a calculation to happen in a specific order that isn’t the default.
  • Division by zero has no defined numeric answer. Entering an expression that divides by zero returns an error rather than a number, since division by zero is mathematically undefined, not simply a very large or very small result.
  • Decimal results are shown to a reasonable number of digits, not truncated to whole numbers. An expression like 10 / 3 returns a decimal result rather than rounding to the nearest whole number, so check the full displayed value if precision matters for what you’re calculating.
  • This calculator’s expression field is the same field the Scientific Calculator uses. Switching modes doesn’t create a separate calculation — it only changes which buttons are shown, so a longer expression already typed stays exactly as entered when you toggle between Normal and Scientific.

Common Mistakes

  • Expecting % to add a percentage of the running total, the way some pocket calculators do. Here, % is a postfix operator that divides just the number right before it by 100 — 200 + 10% evaluates as 200 + 0.1 = 200.1, not 220. To add 10% on top of 200, type 200 + 200 * 10% (or 200 * 1.1) instead.

Worked Example

Evaluating (8 + 4) / 2 - 1:

    1. Evaluate the parentheses first: 8+4=128 + 4 = 12.

    2. Divide: 12÷2=612 \div 2 = 6.

    3. Subtract: 61=56 - 1 = 5.

Useful to Know

Some decimal results look slightly “off” because of how computers store decimal numbers in binary — not because of any error in this calculator. An expression like 0.1 + 0.2 can produce a raw result like 0.30000000000000004 in binary floating-point arithmetic, since most decimal fractions can’t be represented exactly in binary — every calculator and programming language built on standard floating-point math has this same underlying behavior. This calculator rounds displayed results to a sensible number of digits specifically to avoid showing that kind of artifact.

Source: Standard order of operations (PEMDAS/BODMAS).

Frequently Asked Questions

How is this different from the Scientific Calculator?

Both share the same expression field and Normal/Scientific toggle -- this page just opens in the simpler Normal mode by default, with only the everyday +, −, ×, ÷ buttons showing, rather than opening straight into the full trig/log/exponent button set.

Can I still use parentheses or type a longer expression?

Yes -- the expression field accepts anything you type, including parentheses like "(2+3)*4", regardless of which buttons are currently showing on the pad.

Where did the scientific buttons go?

Tap "Scientific" in the toggle above the calculator to switch to the full button set (trig functions, logarithms, exponents, and more) at any time -- your choice is remembered for next time.

Why did my calculation give an unexpected answer, like 10 - 2 * 3 = 4?

This calculator always follows the standard order of operations -- multiplication and division happen before addition and subtraction, regardless of the order the numbers were typed. 10 - 2 * 3 evaluates as 10 - (2 * 3) = 4, not (10 - 2) * 3 = 24. Add your own parentheses whenever you want a specific order.

What happens if I try to divide by zero?

It returns an error rather than a number, since division by zero is mathematically undefined -- not simply a very large or very small result. Check your expression for an accidental zero denominator if you see this.

How does the % button work?

% divides just the number right before it by 100, rather than adding a percentage of a running total the way some pocket calculators do. "200 + 10%" evaluates as 200 + 0.1 = 200.1, not 220 -- to add 10% on top of 200, type "200 + 200 * 10%" (or "200 * 1.1") instead.

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