Free Online Math Calculators: Percentage, Fraction, Algebra & Geometry
Solve maths online for free, from everyday sums to algebra, geometry and statistics. Work out percentages, fractions, averages and standard deviation, solve linear, quadratic, cubic and simultaneous equations, handle matrices and vectors, measure triangles, circles and solids, and convert between number bases. Every answer shows the working.
Choose a Math Tool
of them, from everyday arithmetic to algebra, geometry and number bases. The table underneath matches the question to the tool.
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Which Tool Do I Need?
Find the sentence that sounds like you.
| What you are trying to do | Tool | Why that one |
|---|---|---|
| I need a percentage, a discount or a tax figure | Percentage Calculator | Seventeen different percentage questions, each with its own panel. |
| I have fractions to add, and the answer has to be exact | Fraction Calculator | Whole-number arithmetic throughout, so nothing is rounded on the way. |
| I have a list of numbers and want the average | Average, Mean, Median, Mode Calculator | Mean, median and mode together, because which one you want depends on the data. |
| I need to know how spread out my numbers are | Standard Deviation Calculator | Both the sample and population formulas, so you can see which you are quoting. |
| I have to split something in a ratio, or scale a recipe | Ratio Calculator | And it shows what each part is of the whole, which is where ratios go wrong. |
| I need a common denominator, or the biggest tile that fits | LCM and HCF Calculator | LCM for the first, HCF for the second, and both come out together. |
| I want to pick random numbers or shuffle a draw | Random Number Generator | Unbiased, with or without repeats, from the browser cryptographic source. |
| I need to round something, and get it right | Rounding and Significant Figures Calculator | Seven rules compared, because different software rounds differently. |
| I want to know whether a number is prime | Prime Number Checker | Certain up to 24 digits, with the factors when the number is small enough. |
| I have an ax squared plus bx plus c to solve | Quadratic Equation Solver | Roots, discriminant, vertex, and a check that puts them back in. |
| I need to work out a sum with brackets and powers in it | Scientific Calculator | The whole expression stays on screen, so you can check what you actually asked. |
| I need a power, a square root or a cube root | Exponent and Root Calculator | Exact for whole powers, and it gives the cube root of a negative rather than an error. |
| I need a logarithm, a natural log, or the way back from one | Logarithm Calculator | Any base, with the base stated on every line and the answer shown as a power. |
| I need a factorial, and I need every digit of it | Factorial Calculator | Exact whole-number arithmetic, so 23! and above are right rather than nearly right. |
| I need to count arrangements or selections, nPr or nCr | Permutation and Combination Calculator | Asks whether order and repeats matter, then shows all four counts with yours marked. |
| I need the chance of two things happening, or of at least one in several tries | Probability Calculator | Asks whether the events affect each other before multiplying, which is where the errors come from. |
| I need the mean absolute deviation of a list of numbers | Mean Absolute Deviation Calculator | Around the mean and the median both, with every distance listed and the standard deviation beside it. |
| I need a z-score, or the percentile that goes with it | Z-Score Calculator | Gives the percentile as well, and says plainly when the data shape makes it unreliable. |
| I need a probability from the normal distribution, or a bell curve area | Normal Distribution Calculator | Shades the area it measured, and stays accurate where the usual approximations fail. |
| I need a confidence interval or a standard error | Standard Error and Confidence Interval Calculator | Uses t rather than z on small samples, and states what the interval does and does not claim. |
| I have an equation with one unknown to solve | Linear Equation Solver | Reads the equation as written, shows every step, and names the no-solution and identity cases. |
| I have two or more equations to solve together | Simultaneous Equation Solver | Handles the no-solution and infinitely-many cases properly instead of dividing by zero. |
| I have a cubic equation and need all of its roots | Cubic Equation Solver | Gets repeated roots exactly right, where the plain formula returns two numbers that nearly match. |
| I need to multiply, invert or reduce a matrix | Matrix Calculator | Keeps integer answers integer, and proves the inverse by multiplying it back. |
| I have two points and need the distance, midpoint or slope | Distance, Midpoint and Slope Calculator | Gives all three with the working, and handles a vertical line honestly. |
| I need a dot product, a cross product or the angle between two vectors | Vector Calculator | Keeps the angle accurate on nearly parallel pairs, where the usual formula collapses. |
| I have a right angled triangle and need the missing side | Pythagorean Theorem Calculator | Keeps its accuracy when two sides are nearly equal, and explains an impossible triangle. |
| I need the missing sides, angles or area of a triangle | Triangle Calculator | Area stays accurate on thin triangles, and impossible side sets are explained. |
| I need the area, circumference or a sector of a circle | Circle Calculator | Takes whichever measurement you have, and keeps the segment accurate at small angles. |
| I need the area or perimeter of a four sided shape | Quadrilateral Calculator | Keeps the perpendicular height apart from the slanted side, and refuses impossible shapes. |
| I need the area or angles of a polygon | Polygon Calculator | Handles irregular polygons from coordinates, and never reports a negative area. |
| I need the volume or surface area of a solid | Volume and Surface Area Calculator | Gives both at once, plus the partial surfaces and slant heights people go looking for. |
| I need a number written in a different base | Number Base Converter | Exact at any size, and honest about fractions that cannot be written in the new base. |
| I need bitwise or hex arithmetic that is right past 32 bits | Binary and Hex Calculator | Uses big integers, so a shift past 32 places gives the right answer instead of wrapping. |
| I need to read or write a Roman numeral | Roman Numeral Converter | Reads old spellings such as IIII and still shows the standard form. |
| I need a number in scientific or engineering notation | Scientific Notation Converter | Counts significant figures from what you typed, so a measured trailing zero survives. |
How These Math Tools Work
The same four steps, whichever one you pick.
Why These Rather Than the Usual Calculator Sites
The things that are actually different, not a list of adjectives.
About WizTools Math Tools
Most online calculators do the arithmetic and stop. That is fine when the arithmetic is the whole question, and a surprising amount of the time it is not. Whether you want the mean or the median depends on your data rather than on the sum. Whether standard deviation should divide by n or by n minus 1 depends on where your numbers came from. Whether 2.5 rounds to 2 or 3 depends on which of several perfectly standard rules is in use. In every one of those cases, a single number with no explanation is less useful than it looks.
So these tools are built the other way round. Where there are two defensible answers, both are shown, with the difference on your own numbers. Where a method has a well known failure, the failure is named and the better method is used. And every result comes with the steps that produced it, because a calculator you can check is worth more than one you have to believe.
The arithmetic itself is done carefully, which matters more than it sounds. Fractions are worked out in whole numbers, so a third stays exactly a third instead of becoming 0.333 and drifting. Rounding operates on the digits you typed rather than on the floating point value your browser stored, which is why 2.675 to two places comes out as 2.68 here and 2.67 in most other places. The quadratic solver uses the rearranged formula that does not lose accuracy when the coefficients are far apart. None of these are exotic; they are just the versions that are right.
And none of it goes anywhere. There is no server behind any of these pages, no account, and nothing recorded. Load one, disconnect from the internet, and it carries on working, which is both a privacy property and a reasonable definition of a tool that actually belongs to you.
Frequently Asked Questions
About the set as a whole. Each tool has its own answers too.
Every Other Category
21 more sets of tools on the site. All free, all in your browser.