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Percentage Calculator

A percentage is a part per hundred. To find X% of Y, multiply Y by X ÷ 100: 18% of 64.50 is 11.61. To find what percent one number is of another, divide and multiply by 100. Percent change is (new - old) ÷ old × 100.

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Calculate
%
18% of 64.511.61
64.5 plus 18%76.11
64.5 minus 18%52.89

Percent change = (new - old) ÷ |old| × 100

Change here for the Money line

How to use the Percentage Calculator

  1. Pick a mode: X% of Y, X is what % of Y, or % change.
  2. Enter the two numbers for that mode.
  3. Read the answer as you type; X% of Y also shows Y plus and minus X%.
  4. Switch modes at any time; each keeps its own example values.

Formula

X% of Y = Y × X ÷ 100 · share = part ÷ whole × 100 · change = (new - old) ÷ |old| × 100

Each mode uses one of these three formulas. Percent change divides by the absolute value of the starting number, so a move from -10 to -5 reads as a 50% increase.

Everyday examples

  • Tip: 18% of a $64.50 bill is $11.61.
  • Discount: 30% off $100 leaves $70.
  • Score: 45 out of 60 is 75%.
  • Price rise: $80 to $92 is a 15% increase.

Percent versus percentage points

If a rate goes from 5% to 7%, it rose by 2 percentage points, which is a 40% relative increase. News reports often mix the two, so check which one is meant.

Percentage Calculator questions

How do I calculate what percentage one number is of another?

Divide the part by the whole and multiply by 100. For example, 25 out of 80 is 25 ÷ 80 × 100 = 31.25%. Use the "X is what % of Y" mode, enter the part and the whole, and the percentage appears immediately.

How do I calculate a percentage increase or decrease?

Subtract the old value from the new one, divide by the old value and multiply by 100. A price going from $50 to $60 is (60 - 50) ÷ 50 × 100 = 20% higher. A negative answer means a decrease, so $60 to $50 is a 16.67% drop.

What is the fastest way to calculate a tip?

Find 10% by moving the decimal point one place left, then scale it. On a $40 bill, 10% is $4, so 15% is $6 and 20% is $8. For an exact figure, use "X% of Y" with your tip rate and the bill total.

How do I calculate a discount and the sale price?

Multiply the price by the discount rate to get the saving, then subtract it. For 30% off $100, the saving is $30 and the sale price is $70. In "X% of Y" mode the calculator shows the minus result directly, which is the sale price.

Why is a 50% drop not undone by a 50% rise?

Because each percentage is taken of a different starting number. $100 down 50% is $50, and $50 up 50% is only $75. To get back to $100 from $50 you need a 100% increase. The same effect makes compound returns differ from simple sums.

How do compound percentages work?

Each period's percentage applies to the new total, not the original. A 10% yearly return on $1,000 gives $1,100, then $1,210, then $1,331 after three years, a 33.1% total gain rather than 30%. For longer periods, use the investment calculator.

What is the difference between percentage points and percent change?

Percentage points measure the absolute gap between two percentages; percent change measures the relative gap. Unemployment rising from 5% to 7% is a 2 percentage point rise and a 40% relative increase, since (7 - 5) ÷ 5 × 100 = 40.

How do I convert fractions and decimals to percentages?

Multiply the decimal by 100 and add a percent sign. 3/4 = 0.75 = 75%, and 0.125 = 12.5%. To go the other way, divide by 100: 85% = 0.85, which is 17/20 as a fraction.

What are basis points?

One basis point is one hundredth of a percentage point, or 0.01%, so 100 basis points equal 1%. They are used for interest rates and fees: a mortgage rate moving from 3.25% to 3.50% has risen by 25 basis points.