Free Percentage Calculator Online — Solve Any Percentage Problem Instantly
Our free Percentage Calculator solves all common percentage problems in one place. Whether you need to find a percentage of a number, determine what percentage one number is of another, calculate a percentage increase or decrease, work out a restaurant tip, or apply a discount — this tool covers it all. Every calculation updates in real time as you type, and the formula is shown below every result so you understand the math, not just the answer.
How to calculate a basic percentage (X% of Y)
The most common percentage question is "What is X% of Y?" For example, what is 15% of 200? The formula is: divide the percentage by 100, then multiply by the number. So 15% of 200 = (15 ÷ 100) × 200 = 30. Use the Basic % tab and enter both values — the answer appears instantly.
How to find what percentage one number is of another
To find what percentage X is of Y, divide X by Y and multiply by 100. For example, 30 is what percentage of 200? (30 ÷ 200) × 100 = 15%. This is commonly used for test scores, budget allocations, and proportional comparisons. Use the % of Total tab for these calculations.
How to calculate percentage increase or decrease
Percentage change measures how much a value has grown or shrunk relative to its original value. The formula is: ((New − Old) ÷ |Old|) × 100. A positive result is an increase; a negative result is a decrease. For example, going from 80 to 100 is a 25% increase, while going from 100 to 80 is a 20% decrease. The % Change tab calculates this and clearly labels the direction.
Tip Calculator — how much to tip
The Tip Calculator takes your bill amount and tip percentage and instantly shows the tip amount and the grand total. Common tip percentages (10%, 15%, 18%, 20%, 25%) are available as one-click shortcuts. Enter the number of people to split the bill and you also get the per-person amount automatically.
Discount Calculator — final price after a sale
Enter an original price and a percentage off to instantly see how much you save and what you actually pay. For example, a 200 item at 15% off saves you 30 and costs 170. The formula is: Savings = Price × (Discount% ÷ 100); Final Price = Original − Savings.
Frequently Asked Questions About the Percentage Calculator
What is X% of Y?
Divide X by 100, then multiply by Y. For example, 15% of 200 = (15 ÷ 100) × 200 = 30. Use the Basic % tab — the answer and formula appear instantly as you type.
How do I find what percentage one number is of another?
Divide the part by the total, then multiply by 100. For example, 30 is what percentage of 200? (30 ÷ 200) × 100 = 15%. Use the % of Total tab.
How do I calculate percentage increase?
Use the formula: ((New Value − Old Value) ÷ Old Value) × 100. From 80 to 100: ((100 − 80) ÷ 80) × 100 = 25% increase. The % Change tab handles this and labels the result automatically.
How do I calculate percentage decrease?
Use the same % Change formula. If the new value is smaller than the original, the result is negative, meaning it is a decrease. For example, from 100 to 80: ((80 − 100) ÷ 100) × 100 = −20%, a 20% decrease. The calculator shows "Decrease" clearly.
How do I calculate a tip?
Multiply your bill by the tip percentage divided by 100. For a 120 bill at 18%: Tip = 120 × (18 ÷ 100) = 21.60. Total = 120 + 21.60 = 141.60. The Tip Calculator tab shows this instantly, with common percentages as shortcuts and optional bill splitting.
How do I calculate a discount?
Savings = Price × (Discount% ÷ 100). Final Price = Original Price − Savings. Example: a 200 item at 15% off → Savings = 30 → Final Price = 170. Use the Discount tab to calculate this instantly.
Why is the formula shown below every result?
The formula is displayed so you can understand how the answer was calculated, not just read the number. This is helpful for verifying homework, explaining financial decisions, or learning how percentage math works.
