Percentage Calculator

About the Percentage Calculator and common use cases

This tool performs instant percentage math directly in your browser, covering the three most common forms of percentage calculation: “What is X% of Y”, increase by %, and decrease by %. Everything runs locally—no tracking, no data sharing.

Supported calculations

• What is X% of Y? — Finds a portion of a value (e.g., “What is 15% of 200?” → 30).
• Increase by % — Adds a percentage to a base (e.g., “200 increased by 15%” → 230).
• Decrease by % — Subtracts a percentage from a base (e.g., “200 decreased by 15%” → 170).

Formula breakdown

• X% of Y = (X / 100) × Y
• Increase by % = Base × (1 + % / 100)
• Decrease by % = Base × (1 − % / 100)

Practical use cases

• Finding discounts or sale prices when shopping online or in-store.
• Estimating tips or taxes on restaurant bills and receipts.
• Calculating interest growth or depreciation for finance and budgeting.
• Comparing percentage change between two values for business or data analysis.
• Estimating grade improvements or adjustments in academic contexts.

Example

If a product costs $200 and has a 15% discount, the reduced price is200 × (1 − 15/100) = 170. Similarly, a 15% increase results in $230.

Accuracy and rounding

• All results are rounded to two decimal places for readability.
• For financial applications, confirm rounding rules used by your organization or system.

This percentage calculator is designed for daily math, budgeting, and classroom examples—quick, private, and precise enough for practical use.