Universal Percentage Math
Solve complex percentage variables instantly. Quickly determine margins, reverse tax equations, or calculate raw percental differences.
Percentage Calculator
X% of Y
Result:
What percent is A of B?
Result: %
Increase/Decrease by X%
Increased:
Decreased:
Percentage Change
Change: %
Reverse Percentage (Find Base)
Base Value:
Find Original (Reverse Increase/Decrease)
Original (if increased):
Original (if decreased):
Percentage Points Difference
Difference: points
Sales Tax Calculator
Price with Tax:
Price before Tax:
Stacked Discounts (Double Discount)
Final Price:
Effective Total Discount: %
Price Change & Discount Combo
Price after Markup:
Final Price after Discount:
Net Percentage Change: %
Every Formula You Need
Four separate calculations, kept apart deliberately — because most percentage errors come from answering a different question than the one you meant to ask.
What is X% of Y?
Example: What is 20% of 350? → 70
Best for: Calculating retail discounts, sales tax, server tips, sales commission, or compounding interest.
X is what % of Y?
Example: 45 is what % of 180? → 25%
Best for: Determining exact exam score margins, determining total fraction used against a set quota.
Percentage Increase
Example: Price hiked ₹400 to ₹520 → +30% increase
Best for: Quantifying gross salary bumps, evaluating historical inflation, monitoring year-over-year revenue.
Reverse Percentage
Example: ₹630 after 5% tax → original was ₹600
Best for: Finding original retail cost before an aggressive supplier discount was forcefully applied.
Everyday Arithmetic Workflows
Skip the napkin math. Let our browser-native script solve daily hurdles instantaneously.
Shopping Discount
"A jacket costs ₹2,500 but has a 30% discount. How much do I pay?"
₹2,500 × 30% = ₹750 off → Pay ₹1,750
Restaurant Tip
"My bill is $48.60. I want to leave an 18% tip. How much?"
$48.60 × 18% = $8.75 → Total: $57.35
Salary Hike
"I earn ₹60,000/month. Got a 12% raise. What's my new salary?"
₹60,000 × 12% = ₹7,200 → New: ₹67,200
GST Calculation
"Product costs ₹850 before 18% GST. What's the final price?"
₹850 + (₹850 × 18%) = ₹850 + ₹153 = ₹1,003
Investment Return
"I invested ₹50,000. It's now ₹68,000. What's the return?"
(₹68,000 - ₹50,000) ÷ ₹50,000 × 100 = +36%
Final Grade
"I scored 72 out of 90 marks overall. What's my exact percentage?"
(72 ÷ 90) × 100 = 80%
Frequently Asked Questions
How do I calculate percentage decrease?
Use the "Percentage Change" tab: enter the original (larger) value and the new (smaller) value. The result shows as a negative percentage — e.g. going from 80 to 60 is a -25% change.
What does "reverse percentage" mean?
It finds the original value before a percentage was applied. For example, if a bill totals $120 including a 20% service fee, reverse percentage tells you the pre-fee amount was $100 — useful for backing tax or discounts out of a final price.
What's the difference between percentage change and percentage points?
If an interest rate goes from 4% to 6%, that's a rise of 2 percentage points, but a 50% increase (since 2 is half of 4). Mixing these up is one of the most common percentage mistakes in news and finance.
How do I add GST or tax to a price?
Multiply the base price by the tax rate and add it on: ₹850 with 18% GST is ₹850 + (₹850 × 0.18) = ₹1,003. To remove GST from a final price, use reverse percentage instead — don't just subtract 18%, that gives the wrong answer.
Why can't I just subtract a percentage to undo it?
Because the percentage applies to a different base each way. A 20% increase on 100 gives 120, but a 20% decrease on 120 gives 96, not 100. Undoing a percentage requires dividing by (1 + rate), which is what the reverse percentage mode does.
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About This Tool
Most percentage mistakes come from mixing up two different questions: what a percentage of a number is, and what percentage one number is of another. A third — percentage change — trips people up in a different way, because a 50% fall followed by a 50% rise does not return you to where you started. Each is handled separately here to avoid that confusion.
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