The everyday math,
done for you.

Arithmetic you do all the time — percentages, tips, sales tax, discounts, the better deal, and your pay — each with the formula shown in full.

Percentage Calculator

% of a number, what-percent, and percent change

Tip and split the bill any number of ways

Add tax to a price — or back it out of a total

Sale price and exactly what you save

Which size is actually the better buy

Weekly hours worked, overtime, and pay

Convert hourly pay to annual (and back)

Price from cost — and the markup-vs-margin difference

Plain-English help: how percentages work, markup vs. margin explained, and how to find the best unit price.