Introduction
Percentage calculations appear in discounts, exam scores, growth metrics, tax computations, and data analysis. Three common tasks — finding X% of Y, finding what percent X is of Y, and percent change — each use a slightly different formula.
Numverto Percentage Calculator handles all three modes with step-by-step working. Pair with the Discount Calculator and read our percentage guide.
Core Percentage Formulas
X% of Y = (X/100) × Y. What % is A of B = (A/B) × 100. Percent change = ((New − Old) / Old) × 100. Positive change = increase; negative = decrease.
Step-by-Step Examples
Example: 15% of 2,400
(15/100) × 2400 = 360.
Example: Score 42 out of 50 as percent
(42/50) × 100 = 84%.
Example: Price rise from ₹800 to ₹920
Change = ((920−800)/800) × 100 = 15% increase.
Real-Life Applications
- Exam marks and grade calculation
- Sales growth and KPI reporting
- Tip and tax percentage estimates
- Shopping discount verification
- Statistics and data literacy courses
Advantages of Using This Percentage Calculator
- Three calculation modes in one tool
- Formula shown with substituted numbers
- Handles decimals and large values
- Mobile-friendly numeric keypad inputs
- Links to discount and GST tools
Common Mistakes to Avoid
- Dividing by the new value instead of old in percent change
- Adding percentages incorrectly (10% + 20% ≠ 30% of combined base)
- Confusing percentage points with relative percent change
- Rounding too early in multi-step problems
- Using 0.15 vs 15 inconsistently in formulas
Learn More
Percentage Calculator: Three Tools in One
Percentages are everywhere: discounts, exam scores, tax rates, growth metrics, and statistics. Our percentage calculator handles the three most common percentage problems in one convenient tool with instant results.
1. What is X% of Y?
Formula: Result = Y × X / 100
Example: What is 20% of 500? = 500 × 20 / 100 = 100
Use case: Finding discount amount, tip calculation, tax on a price.
2. X is what percent of Y?
Formula: Percent = (X / Y) × 100
Example: 25 is what % of 200? = (25/200) × 100 = 12.5%
Use case: Exam scores (45 out of 60?), market share, completion rates.
3. Percentage Increase or Decrease
Formula: Change % = ((New - Old) / Old) × 100
Example: Price went from ₹100 to ₹150 = 50% increase
Example: Price dropped from ₹200 to ₹150 = 25% decrease
Quick Percentage Tips
- 10% = divide by 10
- 5% = half of 10%
- 15% = 10% + 5%
- To add 18% GST: multiply by 1.18