Free online percentage calculators for all your percent calculation needs. Calculate percentage change, increase, decrease, difference, and more with instant results.
🔢 Multiple Calculator Types
Access 17 different percentage calculators for every calculation need including basic percentages, changes, increases, decreases, and specialized calculations.
⚡ Instant Results
Get immediate calculations with step-by-step explanations. All calculators show live results as you type with detailed solution breakdowns.
📱 Mobile Friendly
Responsive design works perfectly on desktop, tablet, and mobile devices. Calculate percentages anywhere, anytime.
🎯 Accurate Calculations
Precise calculations with proper rounding and formatting. Handles decimal percentages, negative values, and complex scenarios.
Percentage Calculator
Calculate basic percentages - what is X% of Y, what percent is X of Y, and find the number when percentage is known.
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Percentage Change Calculator
Calculate the percentage change between two values. Shows both increase and decrease with step-by-step solution.
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Percentage Increase Calculator
Calculate percentage increase from one value to another. Find the new value after a percentage increase.
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Percentage Decrease Calculator
Calculate percentage decrease from one value to another. Find the new value after a percentage decrease.
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Percentage Difference Calculator
Calculate the percentage difference between two values. Shows absolute difference as a percentage.
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Fraction to Percent Calculator
Convert fractions to percentages with step-by-step calculations. Handles proper, improper, and mixed fractions.
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Decimal to Percent Calculator
Convert decimal numbers to percentages. Shows the conversion process and handles repeating decimals.
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Average Percentage Calculator
Calculate the average of multiple percentages with different weighting options and statistical analysis.
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Percent Error Calculator
Calculate percentage error between theoretical and experimental values. Essential for scientific calculations.
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Percentage of Percentage Calculator
Calculate a percentage of another percentage. Useful for compound percentage calculations and nested discounts.
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Percentage Point Calculator
Calculate percentage point differences between two percentages. Important for statistical and financial analysis.
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Time Percentage Calculator
Calculate what percentage of time has passed or remains. Perfect for project management and deadlines.
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Percent to Goal Calculator
Calculate how close you are to reaching a goal as a percentage. Track progress towards targets.
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Relative Change Calculator
Calculate relative change as a percentage. Compare values relative to a base or reference point.
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Slope Percentage Calculator
Calculate slope as a percentage from rise and run measurements. Essential for construction and engineering.
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Doubling Time Calculator
Calculate how long it takes for a value to double at a given percentage growth rate. Useful for investments.
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Percentage Increase Classic
Classic percentage increase calculator with additional features for compound growth and multiple time periods.
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Percentages — quick, practical guide
Core idea
Percent means “per 100.” Express any part–whole or change on a 0–100 scale for easy comparison.
How it works
- Find percent: Part ÷ Whole × 100%
- Find part: Percent ÷ 100 × Whole
- Find whole: Part ÷ (Percent ÷ 100)
- Change: (New − Old) ÷ Old × 100%
Sanity checks
- Whole must be > 0 for percent-of calculations
- Same units for part and whole
- Percent can exceed 100% when part > whole
Shortcuts
- 10% of X = X ÷ 10; 1% of X = X ÷ 100
- Increase by p% → multiply by (1 + p/100)
- Decrease by p% → multiply by (1 − p/100)
Pitfalls
- Percent change is not symmetric (+20% then −20% ≠ 0%)
- Percent vs percentage points (12%→15% is +3 pp, +25%)
- Mixed units or baselines give nonsense results
Micro‑examples
- What is 25% of 80? 0.25 × 80 = 20
- 20 is what % of 80? 20/80 × 100 = 25%
- From 50 to 75 → (25/50) × 100 = 50%
Mini‑FAQ
Can percent be over 100%? Yes—when the part exceeds the whole or after large increases.
When to use percentage points? When comparing percentage values directly (e.g., 12%→15% is +3 percentage points).
Action tip
Always state the baseline: “up 12% vs last month” avoids ambiguity and misreads.