Everything You Need to Know About Percentage Calculations
Percentages are everywhere in our daily life: sales, taxes, salary increases, or even cooking recipes. Yet, many of us hesitate on which formula to use. This site gathers all the tools you need to never make a mistake again.
The 3 Essential Formulas
1. Calculate a Part (X% of Y)
Useful for calculating tax amounts or commissions. Multiply the total by the percentage, then divide by 100.
2. Calculate a Discount (Sales)
To get the final price, first calculate the discount amount, then subtract it from the original price. Our 'Add or Remove' tool does this automatically.
3. Calculate a Variation (Evolution)
To find out how much a price has increased (or decreased) as a percentage between two dates, use the formula: ((End - Start) / Start) x 100.
Frequently Asked Questions
It's simple: multiply the price by 0.2. For example, for 20% of $50, calculate 50 x 0.2 = $10. For 30%, multiply by 0.3, etc.
If you have the price including tax (e.g., with 20% tax) and want the pre-tax price, don't just subtract 20%! You need to divide the total by 1.2. Use our 'Reverse Price' tool to avoid mistakes.
To calculate a discount, multiply the price by the discount percentage and subtract the result from the original price. For example, -30% off $100: 100 - (100 × 0.30) = $70. Our 'Add or Remove' tool does this automatically.
A 20% increase means multiplying by 1.20. A 20% decrease means multiplying by 0.80. Caution: increasing by 20% then decreasing by 20% doesn't return to the original price! You need to use reverse calculation to find the starting value.