Free school tools

Percentage calculator

Type 2 numbers and get every percentage answer at once: X% of Y, what percent, the change and the difference.

GPA calculator

Work out your GPA weighted by credits, with honors and AP or IB points, and your new GPA overall.

Chronological age calculator

Chronological age for a test or an assessment, with the borrowing laid out step by step.

Grade calculator

Your grade so far from each part, and what you need on the final for every letter.

Roman numeral converter

Turn numbers into Roman numerals and back, with each step shown, and dates for a tattoo or an engraving.

Fraction calculator

Add, take away, multiply or divide fractions and mixed numbers, with every step and the answer drawn.

Statistics calculator

Paste your numbers and get every statistic at once: mean, median, mode, standard deviation, quartiles and outliers.

Standard deviation calculator

Find the standard deviation of your numbers, sample or population, with the working value by value.

Mean, median and mode calculator

Find the mean, median, mode and range of your numbers, with the list sorted and the middle marked.

Probability calculator

Work out the chance of 2 events, of something happening in repeated tries, or of a lottery-style pick.

Scientific calculator

A free scientific calculator with trig, logs, roots, powers and factorials, in degrees or radians.

Logarithm calculator

Work out a logarithm to any base, natural, common or binary, with the check.

Long division calculator

Divide whole numbers the long way, with every step and repeating decimals marked.

Pythagorean theorem calculator

Find the missing side of a right triangle, with its angles, area and a drawing to scale.