Simple Calculator
Fast, free online calculator for everyday math — add, subtract, multiply, divide, percentages, and square roots. Keyboard friendly.
Keyboard: digits, + − × ÷, = or Enter, Backspace, Escape for clear.
How to use the simple calculator
This calculator handles the four basic operations — addition, subtraction, multiplication, and division — along with percent, square root, and sign toggle. Click the buttons or use your keyboard. Numbers display up to 12 significant digits; anything larger shifts to scientific notation.
The math operations in plain English
Addition (+) combines two amounts. Subtraction (−) removes one amount from another. Multiplication (×) scales one number by another. Division (÷)splits into equal parts. Dividing by zero is undefined mathematically, so the calculator shows "Error" instead of a number.
Percent key behavior
Percent works contextually, the way most desktop calculators do: for addition and subtraction, it treats the second number as a percent of the first (100 + 15% = 115, adding a 15% tip). For multiplication and division, it treats the number as a decimal (250 × 8% = 20, calculating 8% directly).
Square root and sign toggle
The √ button computes the square root of the current display. Negative inputs return an error — for those, use the scientific calculator which handles complex numbers. The ± button flips the sign of the current number — useful when entering negative values mid-calculation.
Order of operations and chaining
Like most pocket calculators, this evaluates left-to-right without operator precedence. Entering 2 + 3 × 4 =gives 20 (computes 2+3 first, then ×4). If you need true PEMDAS behavior, the scientific calculatorevaluates full expressions. You can also chain calculations without pressing "=" — entering 5 + 3 + 2 = computes 10 as expected.
Keyboard tips
Full keyboard support: digits, the standard math symbols (+ - * /), Enter or =for equals, Backspace to erase the last digit, and Escape to fully clear. Delete acts as "CE" — clears the current entry without wiping prior state.
Frequently asked questions
Does this calculator follow order of operations?▾
No — this is a basic arithmetic calculator that evaluates left-to-right, the same way most handheld and phone calculators do. Pressing 2 + 3 × 4 = gives 20, not 14. If you need true order of operations (PEMDAS / BODMAS), use the Scientific Calculator instead, which parses full expressions.
How does the percent key work?▾
It follows the standard Windows-style calculator convention: 100 + 5% gives 105 (5% of 100 added), while 50 × 10% gives 5 (10% as a decimal multiplier). This matches how most people use percent keys for tips and markups.
What keyboard shortcuts are supported?▾
Digits 0-9, decimal point, + − × (*) ÷ (/) for operations, Enter or = for equals, Backspace to erase, Escape to clear, and % for percent. The page captures these keys automatically while focused.
What's the maximum number size?▾
The display shows up to 12 significant digits. Numbers larger than that (or smaller than 0.000001) are shown in scientific notation (e.g., 1.5e+15). Divide-by-zero and invalid square roots show 'Error' — press C to clear.
Is my calculation sent to a server?▾
No. All calculation happens entirely in your browser. Nothing is uploaded or logged. You can use this offline once the page has loaded.
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