Percentage Calculator
Calculate percentages: find X% of a number, what percent one value is of another, or the percentage change between two values.
Frequently Asked Questions
How do I calculate percentage?
To find X% of a number: multiply the number by X and divide by 100. Example: 15% of $80 = 80 × 0.15 = $12. For percentage change: subtract the old value from the new, divide by the absolute old value, and multiply by 100. Example: price went from $50 to $65 → (65−50)/50 × 100 = +30%.
What is 20% of $150?
20% of $150 = $30. To verify: 10% of $150 = $15, doubled = $30. Quick mental math: move the decimal one place left to get 10%, then adjust. For 15%: find 10% ($15) + half of 10% ($7.50) = $22.50.
How do I calculate a percentage increase?
Subtract the original value from the new value, divide by the original value, and multiply by 100. Formula: ((New − Old) / Old) × 100. Example: salary went from $60,000 to $66,000 → (6,000 / 60,000) × 100 = 10% raise.
What percentage is 30 out of 200?
30 out of 200 = 15%. Formula: (30 / 200) × 100 = 15%. This is the same as asking "30 is what percent of 200?" Divide the part by the whole and multiply by 100.
How do I calculate a discount percentage?
Use the percentage change formula. If an item dropped from $80 to $60: ((60 − 80) / 80) × 100 = −25%. Or use "X% of": if it's 25% off $80, the discount is $20, leaving $60. This calculator handles all three forms.