10 percentage modes in one tool: calculate, convert, reverse, and compare with step-by-step solutions.
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Calculation History
To find X% of Y, multiply Y by X and divide by 100. For example, 15% of 200 = 200 × 15 ÷ 100 = 30.
Measures how much a value increased or decreased. Formula: (New − Old) ÷ |Old| × 100. Direction-sensitive.
Compares two values symmetrically using their average. Formula: |V1 − V2| ÷ ((V1 + V2) ÷ 2) × 100. Order doesn't matter.
Find the original price before a markup or discount. If a $60 item had a 20% markup, the original was $60 ÷ 1.20 = $50.
Used in science to compare measured vs. theoretical values. Formula: |Experimental − Theoretical| ÷ |Theoretical| × 100.
Multiply a decimal by 100 to get the percent. Divide a fraction to get the decimal. 3/4 = 0.75 = 75%.
Free percentage calculator with 10 modes: X% of Y, percentage change, percentage difference, reverse percentage (find original price), decimal/fraction converter, percent error, tip calculator, and step-by-step solutions.
To find X% of Y, multiply Y by X and divide by 100. For example, 15% of 200 = 200 × 15 ÷ 100 = 30. This calculator does it instantly as you type and shows each step.
Subtract the old value from the new value, divide by the absolute value of the old value, and multiply by 100. A positive result is an increase; negative is a decrease. Use the % Change mode.
Percentage change is directional: it measures how much a value changed relative to the original. Percentage difference is symmetric: it compares two values relative to their average, so the order does not matter. This tool has separate modes for each.
Use the Reverse % mode. For a discount: divide the sale price by (1 − discount/100). If an item costs $60 after 25% off, the original was $60 ÷ 0.75 = $80. For markup: divide by (1 + markup/100).
Use the Convert mode. Multiply a decimal by 100 to get the percentage (0.75 = 75%). Divide a fraction to get the decimal (3/4 = 0.75). All three representations are shown simultaneously.
Percent error measures how far a measured value is from the expected value: |Experimental − Theoretical| ÷ |Theoretical| × 100. It is commonly used in science labs, engineering, and quality control.
Stacked discounts are applied sequentially, not added. A 30% discount followed by 20% off equals 44% total, not 50%, because the second discount applies to the already-reduced price.
Yes. Use the decimal places selector (gear icon) next to the mode title to choose between 0 and 6 decimal places for all calculations and results.
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