Free & Private Online Browser Utility
Percentage Calculator: Increase & Discount
Solve common percentage equations, relative growth rates, and statistical proportions directly in your browser. This calculator implements six distinct calculation modes: finding X percent of Y, determining what percentage X represents of Y, computing percentage increase or decrease between two values, calculating symmetric percentage difference between two numbers, reconstructing the whole value from a percentage part, and evaluating Compound Annual Growth Rate (CAGR) over multiple periods. Each mode outputs the numerical result alongside step-by-step arithmetic derivations and mathematical formulas. Formula lines format values to 4 decimal places while derivation step totals round to 2 decimal places. Calculations evaluate client-side using floating-point math with zero server transmission.
How to use
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Step 1: Select Calculation Mode
Choose between X% of Y, proportion, relative increase/decrease, percentage difference, whole value, or CAGR.
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Step 2: Provide Input Numbers
Type your numeric values into the corresponding input fields.
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Step 3: Examine Formulas and Steps
Review the computed percentage result and its full arithmetic derivation breakdown.
Worked example
Input: Mode: X% of Y, Percentage rate: 15%, Base value: 200
Output: Result: 30 ((15 ÷ 100) × 200 = 30)
Example calculation; proportion mode confirms 40 is 20% of 200.
Tips & limits
- Percentage change requires a non-zero initial baseline number to avoid division by zero errors.
- For symmetric comparisons without a clear initial baseline, use the Percentage Difference mode.
- All equations evaluate in browser memory; values and inputs are never sent across the internet.
Common problems
- Error: Division by zero is mathematically undefined
Ensure the denominator or baseline value is non-zero when calculating proportions or percentage change.
- Negative CAGR result
CAGR requires positive starting and ending values; a negative result indicates an overall net loss.
Frequently Asked Questions (FAQ)
What is the difference between percentage change and percentage difference?
Percentage change measures directional relative change from a specific starting baseline: ((final - initial) / |initial|) * 100. Percentage difference is non-directional and compares two values against their arithmetic mean: (|x - y| / ((x + y) / 2)) * 100.
How is Compound Annual Growth Rate (CAGR) calculated?
CAGR formula is: ((final_value / initial_value) ^ (1 / years) - 1) * 100. It computes the constant annual geometric rate of return required for an initial sum to grow to a final balance over a specified duration.
How do you calculate what percentage one number is of another?
Divide the partial amount by the total whole value, then multiply by 100: (part / total) * 100. For instance, (40 / 200) * 100 equals 20 percent.
Are my numbers or financial estimates sent to external servers?
No. All percentage arithmetic and exponential power calculations run locally in your web browser session.