Percentage Calculator

Calculate percentages including percentage of values, percentage increase, and percentage decrease.

Percentage = (Part / Whole) x 100; Percent of = (Percent / 100) x Value; % Change = ((New - Old) / Old) x 100
50 is 25% of 200; 25% of 200 = 50; Increase from 50 to 200 = 300%; Decrease from 200 to 50 = 75%

How do I calculate what percentage one number is of another?

Divide the part by the whole and multiply by 100. Formula: (Part / Whole) x 100 = Percentage. Example: 25 is what % of 200? (25 / 200) x 100 = 12.5%. Common use: Test scores (got 42 out of 50 = 84%), sales (sold 75 of 100 units = 75% sell-through rate).

How do I calculate a percentage of a number?

Convert percentage to decimal (divide by 100) and multiply by the number. Example: What is 15% of 80? (15 / 100) x 80 = 12. Quick mental math: 10% = move decimal left one place, then multiply. For 15% of 80: 10% = 8, 5% = 4, so 15% = 12. Useful for tips, discounts, tax.

What is the difference between percentage increase and decrease?

Percentage increase: ((New - Old) / Old) x 100. Example: $100 to $125 = 25% increase. Percentage decrease: ((Old - New) / Old) x 100. Example: $100 to $75 = 25% decrease. Key: Always divide by the ORIGINAL value. A 50% increase from 100 = 150. A 50% decrease from 150 = 75 (not back to 100!).

How do I reverse a percentage calculation?

To find original value: New Value / (1 + Change as decimal). Example: Price after 20% increase is $120. Original = $120 / 1.20 = $100. For decrease: $80 after 20% off = $80 / 0.80 = $100 original. Useful for finding pre-tax prices, original prices before discounts.