Tools in Math

Everyday math tools: percentages, increases and discounts, and grade point average (GPA), explained step by step.

Easy grader calculator for teachersGrade any test in one step: enter the number of questions and how many are wrong to get the percentage, the count correct, and the letter grade A-F.
GPA calculator (4.0 scale)Enter up to 6 courses with grades and credit hours to get your GPA on the 4.0 scale instantly. Free, no sign-up, with the formula fully worked out.
Percentage calculatorFind 25% of 200, what percent one number is of another, plus increase and decrease, all four answers at once. Free, instant, with worked examples.
Z score calculatorCalculate the z score with the formula (x − μ) / σ and get the percentile plus each tail probability. Free, instant, with the formula explained.