Smart Percentage Calculator
Instantly solve all 8 standard percentage calculations with step-by-step formula breakdowns. Fast, private, and local-first.
Basic Percentage (X% of Y)
Find what a specific percentage of any number is.
(20 / 100) × 150 = 30📐 Core Percentage Formulas Reference
Basic (%)
Result = (X / 100) × Y
Example: 20% of 150 = 30.
Proportion (X is % of Y)
Percentage = (Part / Whole) × 100%
Example: 30 out of 150 is 20%.
Percentage Change
Change% = ((New - Old) / Old) × 100%
Example: 100 to 120 is a +20% increase.
Discount & Sale
Final Price = Price × (1 - Discount%)
Example: $200 with 25% off = $150.
Markup
Selling Price = Cost × (1 + Markup%)
Example: $100 cost with 25% markup = $125 price.
Profit Margin
Margin% = ((Selling - Cost) / Selling) × 100%
Example: $80 cost sold at $100 = 20% margin.
❓ Frequently Asked Questions
What is the fundamental difference between markup and profit margin? ▼
Markup is the percentage added to your original cost price to set a selling price. Profit margin is the percentage of the final selling price that remains as profit. Because profit margin divides by the larger selling price, it is always numerically lower than markup for any positive profit.
How does reverse percentage calculation work? ▼
When you know the final value after a tax, discount, or price increase, you cannot simply apply the percentage backwards to the final number. Instead, divide the final number by (1 + rate) for an increase, or by (1 - rate) for a decrease.
Are any numbers sent to external servers? ▼
No. All percentage formulas, discounts, tips, and financial calculations run entirely within your local browser engine. No numerical data or financial amounts are transmitted.