Math Calculators

Answers with the working shown

From everyday percentages and discounts to statistics and quadratic equations, these calculators show each step of the calculation so you can learn the method and check your own work. They are useful for students, teachers, and anyone who needs a quick, reliable answer at work.

Which math calculator do you need?

• Percentages: “what is X% of Y” and its variations with the percentage calculator; increases, decreases and differences with percentage change.
• Fractions and ratios: add, subtract, multiply and divide mixed numbers with the fraction calculator; solve proportions and split amounts with the ratio calculator.
• Algebra: solve ax² + bx + c = 0 with every step using the quadratic equation calculator.
• Statistics: mean, median, variance and standard deviation for a list of numbers.
• School grades: work out your GPA or the score you need on a final with the final grade calculator.

Learning, not just answers

Each calculator shows the formula and the working, so you can follow the method and check your own solution. That makes them useful for homework, for teachers preparing examples and for anyone at work who needs to double-check a figure in a spreadsheet. The explanations under each tool cover common mistakes — such as adding the denominators of fractions or treating a 10% rise and a 10% fall as cancelling out — and how to avoid them.

Quick reference

• X% of Y = Y% of X — 8% of 50 is the same as 50% of 8.
• To undo a percentage increase, divide: a price of 108 after an 8% rise was 108 ÷ 1.08 = 100.
• Successive changes multiply: +10% then −10% gives 0.99, a 1% loss.
• The quadratic discriminant b² − 4ac tells you whether there are two, one or no real roots.
• For normally distributed data, about 68% of values lie within one standard deviation of the mean and 95% within two.