The three most common percentage questions, answered instantly.
X% of Y = X/100 × Y. Percent change = (new − old)/old × 100%.
20% of 150 = 30. Change from 80 to 100 = +25%.
Percentages appear everywhere — sales tax, tips, grades, interest, discounts. This calculator handles the three questions that cover 90% of daily use.
Multiply the price by (1 − discount%). $80 at 25% off = $80 × 0.75 = $60.
A percentage point is an absolute difference (5% → 7% is +2 points, or +40%).
Enter two fractions and pick an operator — get the simplified result.
Type any expression using sin, cos, tan, log, ln, sqrt, ^, pi, e — evaluated safely.
Convert letter grades and credit hours into your weighted grade point average.