Free Online Math Calculator
Calculate complete arithmetic expressions with addition, subtraction, multiplication, division, parentheses, decimals, percentages, roots and powers. Use the keypad or your keyboard, then review a clear result without sending your expression to a server.
Last Updated: July 25, 2026
Basic Math Calculator
Enter one expression, or build it with the buttons. Press Enter or select = to calculate.
How to Use This Math Calculator
- Type a complete arithmetic expression in the display, or select the number and operation buttons.
- Use parentheses when one part must be calculated first. For example, enter
(12+8)*3to get 60. - Select = or press Enter. The calculator follows standard operation precedence.
- Read the result and status message. If the expression is incomplete or undefined, the message explains what to correct.
- Select a recent calculation to load it again. Use Ans to include the last successful result in a new expression.
Your keyboard works with the tool. Use * for multiplication, / for division, ^ for powers and Escape to clear the display. The calculator also accepts familiar symbols such as ×, ÷, − and π. Implicit multiplication works in entries such as 2pi, 2(3+4) and 3sqrt(9).
18+6*(5-2)/3 equals 24. Parentheses give 3, multiplication and division give 6, and the final addition gives 24.What This Online Math Calculator Calculates
This basic math calculator evaluates numerical expressions. It handles the arithmetic used for shopping totals, bills, measurements, homework checks and quick percentage changes. You can combine several operations in one line instead of calculating each part separately.
The tool works with real numbers. It does not solve equations containing variables, show symbolic algebra steps, graph a function or return complex-number answers. Use the related scientific tool when you need trigonometry, logarithms, factorials, angle modes or scientific notation.
| Key or function | Meaning | Example | Result |
|---|---|---|---|
| + | Add values | 28+14 | 42 |
| − | Subtract one value from another | 28-14 | 14 |
| × | Multiply values | 12*7 | 84 |
| ÷ | Divide by a non-zero value | 84/7 | 12 |
| % | Percentage or percentage change | 200+10% | 220 |
| ( ) | Calculate grouped work first | (8+4)*3 | 36 |
| x² and xʸ | Squares and powers | 5^3 | 125 |
| √x and ∛x | Square root and cube root | cbrt(-27) | −3 |
| 1/x | Reciprocal of a non-zero value | 1/(8) | 0.125 |
| π and e | Common mathematical constants | 2*pi | 6.28318530718 |
Basic Math Formulas Used
The calculator applies defined arithmetic rules rather than sending the expression to a search service. It keeps the browser's internal numeric value during evaluation, then formats the visible result to a practical number of significant digits.
Addition, subtraction, multiplication and division
Subtraction: a − b
Multiplication: a × b
Division: a ÷ b, where b ≠ 0
Addition combines quantities, while subtraction finds a difference. Multiplication represents repeated scaling. Division separates a quantity into equal parts or finds a ratio. Division by zero has no finite real-number result, so the calculator returns a clear error.
Percentages and percentage change
p% of x = x × p ÷ 100
Increase x by p% = x × (1 + p ÷ 100)
Decrease x by p% = x × (1 − p ÷ 100)
The percentage key uses familiar calculator behavior. A percentage by itself becomes a decimal, so 50% equals 0.5. With multiplication, 250*18% equals 45. With addition or subtraction, a standalone percentage applies to the current subtotal. Therefore, 200+10% equals 220 and 200-10% equals 180.
Successive percentage changes use the updated subtotal. The expression 100+10%+10% equals 121, not 120. The first 10% raises 100 to 110. The second 10% is then calculated from 110. This compounding rule matters when comparing repeated increases or decreases.
Powers, roots and reciprocals
Square: x² = x × x
Square root: √x = x^(1/2), where x ≥ 0 in real-number mode
Cube root: ∛x = cbrt(x)
Reciprocal: 1/x, where x ≠ 0
Powers associate from right to left, so 2^3^2 means 2^(3²) and equals 512. A square root needs a non-negative input in this real-number calculator. Cube roots accept negative values, which is why cbrt(-27) returns −3.
Worked Math Calculator Example
Evaluate 240+15%-18/3. This example combines a percentage increase with division and subtraction.
| Step | Calculation | Value |
|---|---|---|
| Find 15% of the subtotal | 240 × 15 ÷ 100 | 36 |
| Apply the increase | 240 + 36 | 276 |
| Perform division | 18 ÷ 3 | 6 |
| Subtract the final term | 276 − 6 | 270 |
The final result is 270. The calculator recognizes 15% as a percentage of the subtotal to its left because it is the direct right operand of addition. Division in the separate final term is evaluated before that term is subtracted.
Order of Operations: PEMDAS and BODMAS
PEMDAS and BODMAS are memory aids for the same core operation order. Parentheses or brackets come first. Powers and roots follow. Multiplication and division come next. Addition and subtraction come last.
Operations at the same level run from left to right. For example, 18/3*2 equals 12 because 18 ÷ 3 is 6, then 6 × 2 is 12. Multiplication does not automatically occur before division. The same left-to-right rule applies to addition and subtraction.
Parentheses change the grouping. The expression 2+3*4 equals 14, while (2+3)*4 equals 20. Add parentheses whenever the intended grouping might be unclear.
Negative numbers and powers
A leading minus sign applies after a power unless parentheses make the negative value the base. Therefore, -2^2 equals −4, while (-2)^2 equals 4. Use the ± button to wrap the current expression as a negative value.
Everyday Uses for a Basic Math Calculator
- Shopping: total several prices, estimate a discount or apply a percentage increase.
- Bill splitting: divide a total by the number of people and keep decimal precision until the final amount.
- Measurements: combine lengths, multiply dimensions or check a square-root calculation.
- Homework checking: verify arithmetic after showing the method required by your course.
- Budget estimates: compare simple totals and percentage changes without assuming a currency.
- Repeated work: store a value in memory, reuse the previous answer or reload an expression from recent history.
Always keep units consistent. Adding 3 metres to 40 centimetres directly produces a misleading result unless one value is converted first. This calculator evaluates numbers, but it cannot infer the intended unit or decide whether a formula fits your situation.
Basic vs Scientific vs Specialized Calculators
| Calculator type | Best for | Typical functions | Main limit |
|---|---|---|---|
| Basic Math Calculator | Everyday numerical expressions | Arithmetic, percentages, parentheses, roots and powers | No trig, logs or symbolic solving |
| Scientific Calculator | Science, engineering and advanced coursework | Trig, inverse trig, logs, factorials and angle modes | No graph plotting or symbolic algebra |
| Average Calculator | Summarizing a list of numbers | Mean, sum, count, minimum, maximum and range | Designed for datasets, not mixed expressions |
| Time Calculator | Duration arithmetic | Add, subtract and compare hours, minutes and seconds | Uses time units rather than plain decimals |
Accuracy, Rounding and Calculator Limits
The calculator uses the browser's standard double-precision number format. It keeps more precision internally than it normally displays. The visible result uses up to 12 significant digits and removes common binary floating-point noise, so 0.1+0.2 displays as 0.3.
Some decimal values cannot be stored exactly in binary. Long calculations, values near the supported numeric limit and repeated rounding may produce a small difference in the final digits. Keep adequate precision during intermediate steps and apply the rounding rule required by your class, contract or professional standard only at the end.
The tool limits expression length, token count and parenthesis depth to keep input predictable. It rejects division by zero, square roots of negative values, 0^0, non-real negative-base powers and results outside the supported finite range. These messages identify a mathematical or input limit rather than silently returning an unreliable value.
Privacy and Calculation Method
Your expression is parsed and calculated in the browser by the code on this page. The calculator does not submit expression text to a calculation server. Memory and recent history remain in the current page session and disappear when the page reloads.
The implementation uses a defined tokenizer and expression parser. It accepts only supported numbers, constants, functions, operators and parentheses. It does not run the expression as general JavaScript code. This approach also lets the calculator return specific messages for incomplete expressions, unsupported names and missing parentheses.
Related Calculators
Frequently Asked Questions
What is a math calculator?
A math calculator evaluates numerical expressions using defined arithmetic rules. This tool supports common operations, percentages, parentheses, roots, powers, constants and memory.
Does this calculator follow PEMDAS or BODMAS?
Yes. It calculates parentheses first, then powers and roots, then multiplication and division, and finally addition and subtraction. Operations at the same level run from left to right.
How does the percentage key work?
A percentage alone is divided by 100. In addition or subtraction, a standalone percentage applies to the current subtotal. For example, 200+10% equals 220 and 200-10% equals 180.
Does the calculator support decimals and negative numbers?
Yes. You can enter decimals, unary negative values and grouped negative values. Parentheses are important around a negative base raised to a power.
Can I use my keyboard?
Yes. Type numbers and operators directly, press Enter to calculate and press Escape to clear. Use an asterisk for multiplication, a slash for division and a caret for powers.
Why is division by zero undefined?
No finite real number multiplied by zero produces a non-zero numerator. The calculator therefore blocks division by zero instead of displaying an infinite or misleading result.
Why do some decimal results need rounding?
Browsers store numbers in binary double precision, and some decimal fractions do not have an exact binary representation. The display removes common noise, but you should apply the required final rounding rule.
Can this calculator solve equations with variables?
No. It evaluates numerical expressions only. It does not isolate variables, simplify symbolic algebra or show equation-solving steps.
What is the difference between this and a scientific calculator?
This page focuses on everyday arithmetic. The Scientific Calculator adds trigonometry, inverse trigonometry, logarithms, factorials, scientific notation and angle modes.
Are my calculations stored or sent to a server?
The expression is calculated in your browser. Memory and recent history stay in the current page session and are cleared when the page reloads.