Free Online Percentage, Fraction, Average, Ratio & Statistics Calculator Tools
Solve everyday maths online for free. Work out percentages, discounts and tax, add or simplify fractions, find the average, median and mode, calculate standard deviation, reduce ratios, check prime numbers and solve quadratic equations. Every answer shows the working, so you can follow each step.
Choose a Math Tool
Ten of them. 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. |
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
17 more sets of tools on the site. All free, all in your browser.