Percentage Calculator
Eight percentage calculators, each showing the working for its answer.
Percentage of a number
15% of 2,400 is 360.
15 ÷ 100 × 2,400 = 360
What percent is it?
45 is 75% of 60.
45 ÷ 60 × 100 = 75%
Find the total
30 is 12% of 250.
30 ÷ 12 × 100 = 250
Percentage change
From 80 to 100 is an increase of 25%.
(100 − 80) ÷ 80 × 100 = +25%
Difference: +20
Increase or decrease, measured from the old value.
Add or take off a percentage
1,000 increased by 18% is 1,180.
1,000 + (18% of 1,000) = 1,000 + 180 = 1,180
Increase of 180
Value before a percentage change
1,000 increased by 18% gives 1,180.
1,180 ÷ (1 + 18 ÷ 100) = 1,180 ÷ 1.18 = 1,000
Increase of 180
Undo a markup, tax or discount: divide, don’t subtract.
Percentage difference
40 and 60 differ by 40% of their average.
|40 − 60| ÷ ((40 + 60) ÷ 2) × 100 = 20 ÷ 50 × 100 = 40%
No direction: compared with the average of the two.
Percentage points
6.5% to 7.25% is a rise of 0.75 percentage points, an increase of about 11.54% relative to 6.5%.
7.25% − 6.5% = +0.75 percentage points
Relative change: ≈ +11.54% — (7.25 − 6.5) ÷ 6.5 × 100
Points are the plain difference; percent is relative to the start.
About the Percentage Calculator
Eight small calculators cover the percentage questions people actually ask: what is 15% of 2,400, what percent 45 is of 60, the percentage change from 80 to 100, adding or taking off a percentage, finding the original value before an increase, the percentage difference between two numbers, and the change between two rates in percentage points.
Every answer comes with the working, using your numbers, so you can check it or reuse the method. Results update as you type, and you choose how many decimal places to show.
How to use it
- Pick the calculator that matches your question. Each one reads as a sentence, for example What is 15% of 2,400?
- Type your numbers. Commas, ₹ and % signs are fine (1,00,000 or 12.5%).
- Read the answer and the working underneath it. Copy copies the plain number, ready to paste into a spreadsheet.
- Change Decimal places for more or less precision. Rounded answers are marked with ≈.
Examples
360 (15 ÷ 100 × 2,400)
+25% ((100 − 80) ÷ 80 × 100)
Going back from 100 to 80 is a 20% decrease, not 25%, because the change is measured from a bigger starting value.
1,000 (1,180 ÷ 1.18)
Taking 18% off 1,180 gives 967.60, which is wrong. To undo an increase, divide.
+0.75 percentage points, a relative increase of ≈ 11.54%
Common uses
- Working out marks, scores and pass percentages.
- Checking a price rise, a salary hike or a fall in sales as a percentage.
- Finding the price before tax or before a markup was added.
- Comparing interest rates, returns or survey results in percentage points.
The formulas
- X% of Y = X ÷ 100 × Y
- X as a percentage of Y = X ÷ Y × 100
- X is P% of what? = X ÷ P × 100
- Percentage change = (new − old) ÷ |old| × 100
- Increase Y by P% = Y × (1 + P ÷ 100); decrease = Y × (1 − P ÷ 100)
- Value before a P% increase = final ÷ (1 + P ÷ 100); before a decrease = final ÷ (1 − P ÷ 100)
- Percentage difference = |A − B| ÷ ((|A| + |B|) ÷ 2) × 100
- Percentage points = new percentage − old percentage
Percent or percentage points?
When a rate moves from 8% to 10%, it has risen by 2 percentage points — the plain difference — but by 25% relative to where it started (2 ÷ 8 × 100). Loan rates, election results and exam pass rates are often reported both ways, which causes confusion.
Use percentage points (pp) for the difference between two percentages and percent for relative change. In finance, one hundredth of a percentage point is a basis point: a 0.25 pp change in an interest rate is 25 basis points.
Why percentage changes do not cancel out
A 25% rise followed by a 25% fall does not bring you back to the start: 100 → 125 → 93.75. The fall is 25% of a bigger number. For the same reason, to remove an 18% increase from 1,180 you divide by 1.18 (giving 1,000) rather than subtracting 18% of 1,180.
Limitations
- Calculations use standard double-precision arithmetic, rounded for display. Numbers above 10¹⁵ are rejected because they cannot be stored exactly.
- A percentage change from 0 is undefined, so that calculator needs a starting value other than 0.
- Percentage difference uses the average of the two absolute values as its base; some fields use a different convention.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. 15% of 2,400 = 15 × 2,400 ÷ 100 = 360. In your head: 10% is the number with the decimal point moved one place left (240), and 5% is half of that (120), so 15% is 360.
How do I work out a percentage increase?
Subtract the old value from the new value, divide by the old value and multiply by 100. From 80 to 100: (100 − 80) ÷ 80 × 100 = 25%. A negative result is a decrease.
Is percentage difference the same as percentage change?
No. Percentage change has a direction — from an old value to a new one — and divides by the old value. Percentage difference compares two values without a direction and divides by their average. So 40 and 60 differ by 40%, while 40 → 60 is a 50% increase and 60 → 40 is a 33.33% decrease.
What is a percentage point?
It is the unit for the plain difference between two percentages. A home-loan rate rising from 8.5% to 9% has gone up by 0.5 percentage points (50 basis points), which is a 5.88% increase in the rate itself.
How do I find the original price before a discount?
Divide the sale price by (1 − discount ÷ 100). A price of ₹1,499.25 after 25% off was ₹1,499.25 ÷ 0.75 = ₹1,999. The discount calculator does this and also handles stacked discounts and GST.