Three of the most common percentage questions, each in its own live section. "What percent is X of Y" divides X by Y and multiplies by 100 — useful for scores, discounts spent, or shares of a total. "What is Y% of X" multiplies X by Y/100 — the classic tip, tax or commission calculation. "Percentage change from X to Y" computes (Y − X) / X × 100, giving a positive number for an increase and a negative number for a decrease, with a label so you can tell them apart at a glance.
Every field recalculates as you type, so you can experiment without pressing a button. Results are rounded to two decimals for readability; if the base of a percent-change is zero the change is undefined and the tool leaves it blank. All arithmetic happens in your browser and nothing is uploaded.