Everyday Math

Percentages, proportions, discounts and bill splitting.

Percentage calculatorCalculate X% of a value, what percentage one number is of another, and the percent change between two values.
Rule of threeSolve simple proportions: if A is to B, then C is to D. With practical examples and the difference between direct and inverse proportion.
Discount calculatorCalculate the final discounted price and how much you save. Table by discount tier and the traps of stacked discounts.
Tip calculatorCalculate the tip, the total bill and each person's share. With tipping conventions for the US and abroad.