Percentage Calculator

Step-by-step

1. Enter the base value in Number, such as a price or a total budget.
2. Enter the rate in Percent as a plain number, without the % sign. For 15 percent, type 15.
3. Click Calculate. The result, that percentage of your number, appears right below.
4. To get a discounted or increased amount, subtract the result from your original number or add it on.

Example

A jacket costs 1,250 and is 20% off. Put 1250 in Number and 20 in Percent, and the result is 250. That's the discount, so you pay 1,250 minus 250, which is 1,000. The same two fields handle a 10% tip on a bill or show you how much a raise is worth in actual money.

Percentage change needs its own formula: (new value minus old value) divided by old value, times 100. If a price goes from 80 to 100, that's a 25% increase. If it drops from 100 to 80, that's a 20% decrease. The gap is 20 either way, but the percentage depends on where you start.

Percentage formulas

• Percentage of a number: number × percent ÷ 100. This is exactly what the tool does. Example: 80% of 289 = 289 × 80 ÷ 100 = 231.2.
• What percent one number is of another: (part ÷ whole) × 100. To find what percent 45 is of 180: 45 ÷ 180 = 0.25, so 25%.
• Increase by a percentage: number × (1 + percent ÷ 100). Adding 18% to 200 gives 200 × 1.18 = 236.
• Decrease by a percentage: number × (1 − percent ÷ 100). A 20% discount on 1,250 gives 1,250 × 0.80 = 1,000.
• Percentage change: (new value − old value) ÷ old value × 100.

The two fields in the tool (Number and Percent) calculate the first formula. For the others, work out the percentage with the tool first, then add or subtract the result by hand.

Worked examples

• 80% of 289: 231.2.
• 18% of 1,000: 180. If 18% tax is added to a 1,000 amount, this is the amount added.
• 15% of 750: 112.5.
• A 30% raise on a 2,500 salary: 2,500 × 30 ÷ 100 = 750 more, so the new salary is 3,250.
• 12% off a 24,000 phone: 24,000 × 12 ÷ 100 = 2,880 off, so you pay 21,120.
• Common percentages of 1,000: 5% = 50, 10% = 100, 25% = 250, 50% = 500, 75% = 750.

Mental math shortcuts

• 10%: divide the number by 10, which means moving the decimal point one place left (10% of 350 is 35).
• 50%: half the number. 25%: a quarter of the number.
• 5%: find 10% first, then halve it. 20%: twice 10%.
• 15%: add 10% and 5% (15% of 200: 20 + 10 = 30).

Common calculations

What is 80 percent of 289?

80% of 289 is 231.2: 289 × 80 ÷ 100 = 231.2.

How do I calculate a percentage?

The percentage of a number is number × percent ÷ 100. For example, 15% of 750 is 750 × 15 ÷ 100 = 112.5.

How do I find a percentage increase or discount?

For an increase, multiply by (1 + percent ÷ 100): adding 18% to 200 gives 236. For a discount, multiply by (1 − percent ÷ 100): 20% off 1,250 gives 1,000.

Is 47 times 200 a percentage?

No. 47 notes of 200 are worth 47 × 200 = 9,400. That is a multiplication, not a percentage.

Things to keep in mind

• Percent and percentage points are different. An interest rate moving from 10% to 12% is a 2-point rise, which is a 20% increase in the rate itself.
• A 50% increase followed by a 50% cut doesn't bring you back to the start: 100 becomes 150, then 75.
• With decimals you may need to round to the cent. For official calculations, check which rounding rule applies.
• For tax or payroll work, confirm the current rates with the relevant official source before relying on any result.