Math and learning tools
Calculators and study aids for homework, revision and quick checks. Check the conventions each tool states, such as rounding and angle units, before copying a result.
Calculate and inspect mathematical results
Scientific calculator
Trigonometry, logs, powers, constants, memory and history, with keyboard input.
Percentage and ratio calculator
X% of Y, percentage change, what percent, and ratio simplification and scaling.
Fraction calculator
Add, subtract, multiply and divide fractions and mixed numbers, with steps.
Statistics calculator
Mean, median, mode, standard deviation, quartiles, and normal/binomial/t probabilities.
Unit converter
Length, mass, temperature, volume, area, speed, data, energy, pressure and more.
Graph and solve
Plan grades and organize study
Guides
- Percentages, percentage change and percentage points: The three basic percentage calculations, why +50% then −50% does not get you back, percentage points versus percent, and other mistakes that mislead.