Percentage Calculator

The Percentage Calculator handles every everyday percentage problem you're likely to run into: finding X% of a number, expressing one number as a percentage of another, computing percentage increase or decrease between two values, and reverse-calculating an original amount from a percentage change. Instead of remembering the formula for each case, pick the right mode and the tool does the arithmetic. Percentages come up constantly. Retail discounts ("30% off"), exam scores ("47 out of 60 = 78.33%"), interest rates on loans and deposits, GST slabs, salary hikes, stock returns, bill splitting, tip calculations, tax brackets, election vote shares, weight loss and fitness goals, growth rates in business, and portfolio allocations are all percentage math dressed up in different language. Getting the calculation right — especially the difference between "increased by 20%" and "is 20% of" — matters more than most people realise. Key formulas the tool uses: - X% of Y = (X ÷ 100) × Y. What is 15% of 800? = 0.15 × 800 = 120. - Y is what % of Z = (Y ÷ Z) × 100. 47 is what % of 60? = (47 ÷ 60) × 100 = 78.33%. - Percentage change = ((New − Old) ÷ Old) × 100. From 100 to 125 = 25% increase. From 100 to 75 = 25% decrease. - Reverse increase: if a price after 18% GST is ₹590, the pre-GST base = 590 ÷ 1.18 = ₹500. - Reverse decrease: if a sale price after 30% off is ₹1,050, the original = 1,050 ÷ 0.70 = ₹1,500. Common traps to watch for. A 50% loss followed by a 50% gain does not get you back to break-even — it leaves you at 75% of your starting value (100 → 50 → 75). To recover a 50% loss, you need a 100% gain from the low. This asymmetry is why controlling downside matters so much in investing. Similarly, "20% cheaper than X" and "X is 20% more than the cheap one" are different equations — the first means new = 0.80 × X, the second means old = new × 1.20. Use the tool for quick exam prep, invoice checking, discount verification during sales, computing tax-inclusive and tax-exclusive prices, and any other percentage work. Combine it with the GST Calculator for Indian tax math, the EMI Calculator for interest computations, and the CGPA Calculator for grade-to-percentage conversions. Everything runs client-side — no data is uploaded or logged.