Calculator0
Online Calculator
Use our free Online Calculator as a fast math calculator for addition, subtraction, multiplication, division, percentages, decimals and parentheses.
Use our free Online Calculator as a fast math calculator for addition, subtraction, multiplication, division, percentages, decimals and parentheses.
For a quick calculation, enter the numbers and operators in the same order you would write the expression on paper. Use parentheses when one part of the expression must be evaluated first, and use the clear or delete controls if you need to correct an entry without starting over.
A basic calculator covers the arithmetic used in shopping, bills, schoolwork, budgeting and quick checks. The table below shows the most common operations and the search questions they answer.
| Operation | What it does | Example |
|---|---|---|
| Addition (+) | Combines values | 42 + 18 = 60 |
| Subtraction (−) | Finds a difference | 90 − 37 = 53 |
| Multiplication (×) | Repeated addition or scaling | 24 × 6 = 144 |
| Division (÷) | Splits or forms a ratio | 144 ÷ 12 = 12 |
| Percentage (%) | Works with parts per hundred | 15% of 200 = 30 |
| Parentheses | Controls calculation order | (8 + 4) × 3 = 36 |
Percentage questions are among the most common reasons people use an online calculator. A percentage means “per hundred,” so 15% is equivalent to 0.15.
For a 20% discount, multiply the original price by 0.80. For a 20% increase, multiply by 1.20. This is often faster and less error-prone than calculating the change separately.
When an expression contains several operators, the calculator follows normal mathematical precedence. Parentheses come first, then powers where available, followed by multiplication and division, and finally addition and subtraction. Multiplication and division at the same level are evaluated in sequence, as are addition and subtraction.
This is why 10 + 5 × 2 is 20 rather than 30. If you intend 30, enter (10 + 5) × 2. Explicit parentheses are the safest way to communicate your intended calculation.
Decimals are useful for money, measurements and ratios. Negative numbers can represent debt, temperatures below zero, losses or movement in the opposite direction. The calculator can evaluate these values directly, but the displayed result may contain more decimal places than the precision of the original data.
When a result is used for a real measurement, round only at the end of the calculation. Repeatedly rounding intermediate steps can introduce avoidable error.
| Question | Expression | Result |
|---|---|---|
| What is 12% of 480? | 480 × 0.12 | 57.6 |
| Add 8% tax to 125 | 125 × 1.08 | 135 |
| Split 945 equally among 7 | 945 ÷ 7 | 135 |
| Average of 14, 18 and 22 | (14 + 18 + 22) ÷ 3 | 18 |
| Decrease 240 by 15% | 240 × 0.85 | 204 |
| Evaluate a grouped expression | (36 − 12) ÷ 4 | 6 |
These examples cover common informational searches such as percentage calculator, discount calculator, average calculation and basic arithmetic. For trigonometry, logarithms, roots or powers, use the Scientific Calculator.
If a result looks surprising, first re-read the expression exactly as the calculator received it. Most unexpected basic-calculator results come from entry order or parentheses rather than from the arithmetic itself.
Choose the tool that matches the calculation you need. The Online Calculator is fastest for arithmetic and percentages. The Scientific Calculator is better for trigonometry, logarithms, powers, roots and constants such as π. The Math Solver is designed for supported equations and symbolic problems where you want to solve for a variable or inspect mathematical working.
| Need | Best tool |
|---|---|
| Everyday arithmetic and percentages | Online Calculator |
| sin, cos, tan, log, ln, powers, roots | Scientific Calculator |
| Solve an equation or supported symbolic expression | Math Solver |
| Convert measurement units | Unit Converter |
Percentages answer several different questions, so it helps to identify which quantity is unknown before entering the numbers. To find a percentage of a value, convert the percentage to a decimal and multiply. To find what percentage one number is of another, divide the part by the whole and multiply by 100. To find the original value before a percentage increase or discount, divide the final value by the remaining or increased percentage factor.
| Question | Formula | Example |
|---|---|---|
| What is 18% of 250? | 250 × 0.18 | 45 |
| 45 is what percent of 250? | 45 ÷ 250 × 100 | 18% |
| Increase 250 by 18% | 250 × 1.18 | 295 |
| Decrease 250 by 18% | 250 × 0.82 | 205 |
| 205 is the price after 18% off. Original? | 205 ÷ 0.82 | 250 |
Reverse percentages are where many quick calculations go wrong. If a price falls by 20%, adding 20% to the reduced price does not return to the original because the second percentage is applied to a smaller base.
Everyday money calculations often combine a base price with one or more percentages. A discount reduces the base; tax or a service charge usually increases the discounted subtotal; a tip may be calculated on the subtotal or on the final bill depending on your preference.
For a markup, multiply cost by 1 plus the markup rate. A 35% markup on a $40 cost is 40 × 1.35 = $54. Markup and profit margin are not the same concept: a 35% markup is measured against cost, while margin is measured against the selling price.
A fraction is a division statement. Converting a fraction to a decimal means dividing the numerator by the denominator. Converting a terminating decimal to a percentage means multiplying by 100. These forms are interchangeable representations of the same value.
| Fraction | Decimal | Percentage |
|---|---|---|
| 1/2 | 0.5 | 50% |
| 1/4 | 0.25 | 25% |
| 3/4 | 0.75 | 75% |
| 1/5 | 0.2 | 20% |
| 1/8 | 0.125 | 12.5% |
| 2/3 | 0.666… | 66.666…% |
When a decimal repeats, keep extra precision during intermediate steps and round only the final answer. Early rounding can produce a noticeable error when several operations are chained together.
Ratios compare quantities, while a rate compares quantities with different units. If 3 notebooks cost $12, the unit rate is 12 ÷ 3 = $4 per notebook. If a recipe for 4 people uses 300 g of an ingredient and you need 10 servings, multiply by 10 ÷ 4, giving 750 g.
For proportions such as a/b = c/d, cross multiplication gives a×d = b×c. This is useful for scaling recipes, maps, mixture ratios and simple conversions when the relationship is proportional.
Division asks how many times one quantity fits into another. Dividing by zero has no finite real-number result, so an expression such as 5 ÷ 0 is undefined rather than an extremely large number. Likewise, 0 ÷ 0 is indeterminate because many different values could satisfy the corresponding multiplication statement.
If a calculation returns an error, check for a zero denominator, an incomplete expression, mismatched parentheses or an operation that requires the Scientific Calculator instead.
Round according to the purpose of the calculation. Currency is commonly displayed to two decimal places, but taxes, exchange calculations and rates may require more precision internally before the final amount is rounded. Measurements should normally reflect the precision of the source data rather than showing many meaningless digits.
| Use | Typical approach |
|---|---|
| Currency total | Keep precision during calculation; round final displayed amount to the currency unit used. |
| Measurement | Do not imply more precision than the original measurement supports. |
| Percentage rate | Keep several decimal places if it will be reused in another calculation. |
| Estimate | Round early only when the purpose is a quick mental check. |
A quick estimate catches many typing errors. If 49.8 × 20.2 produces a result near 1,000, that is reasonable because 50 × 20 = 1,000. If the screen instead shows 10,000, check the decimal point and operators before using the result.
For division, reverse the operation when practical. If 936 ÷ 24 = 39, then 39 × 24 should return 936. For percentages, compare the answer with the whole: 5% of a number should be much smaller than 50% of the same number.
Yes. The calculator is available directly on the page without an account.
Multiply the value by the percentage divided by 100. For example, 15% of 200 is 200 × 0.15 = 30.
Yes. Multi-step expressions follow normal mathematical precedence; use parentheses whenever you need to control the order explicitly.
Convert the discount to a decimal and subtract it from 1. A 25% discount means multiplying the original price by 0.75.
Convert the percentage to a decimal and add it to 1. For example, adding 8% means multiplying by 1.08.
Some operations produce non-terminating or long decimal results. Round only to the precision appropriate for your use case.
Yes. Negative values can be entered for calculations involving debt, loss, temperatures below zero and similar cases.
Use it for trigonometry, logarithms, roots, powers and other scientific functions.
Use Math Solver when the task is to solve a supported equation or symbolic problem rather than only evaluate a number.
Division by zero is undefined in ordinary arithmetic and does not produce a finite numeric result.
Divide the discounted price by 1 minus the discount rate written as a decimal. For example, a price after 20% off is divided by 0.80.
Subtract the old value from the new value, divide by the old value, then multiply by 100.
The increase is applied to the reduced value, so it uses a different base.
Usually keep extra precision through intermediate steps and round the final result for the purpose of the calculation.