# Percentage & Ratio Calculator

> Calculate percentages five ways: what X% of Y is, what percent one number is of another, percentage change, add/subtract a percent, and multi-part ratio splits — with formulas shown, free, in your browser.

A five-in-one percentage and ratio calculator. Switch between the exact problems people actually need to solve — find a percentage of a value, work out what percent one number is of another, measure percentage increase or decrease, add or subtract a percent, and split a total across any multi-part ratio. Each mode shows the result live with the formula behind it and a visual breakdown.

- **Live tool:** https://www.toolnova.org/utilities/percentage-ratio-calculator
- **Category:** Calculators & Converters (https://www.toolnova.org/utilities)
- **Price:** Free
- **Requirements:** Runs in a modern web browser · No signup · No install

## What this tool does

- Five modes: % of value, X-is-what-%, % change, add/subtract %, ratio split
- Multi-part ratio splitter (3:2:1 and beyond) with stacked bar chart
- Percentage increase and decrease with absolute change and growth factor
- Every result shows the underlying formula for learning and checking
- Live updates as you type — no calculate button needed

## How to use Percentage & Ratio Calculator

1. **Choose the calculation mode** — Pick from '% of value', 'X is what %', '% change', 'Add / subtract %', or 'Ratio split' depending on the problem you're solving.
2. **Enter your numbers** — Type the values into the labelled fields. For ratio split, enter the total and a ratio like 60:40:20 — it accepts any number of parts.
3. **Read the result and formula** — The big result updates instantly, with the formula shown beneath it so you can see exactly how the answer was derived.

## Common use cases

- Working out a discount, tip, tax, or commission amount
- Finding what percentage a score or part is of a total
- Measuring percentage growth or decline between two figures
- Adding markup or removing a discount from a price
- Splitting a budget, bill, profit, or inheritance by ratio
- Checking homework or verifying a spreadsheet calculation

## About

### Solve percentages and ratios without the mental math

This calculator covers the everyday percentage problems people actually search for: what percent one number is of another, percentage increase or decrease, adding or removing a percentage, and simplifying or scaling ratios. Type the numbers and read the answer — no formula recall required.

### Practical for finance, study, and cooking

Whether you're checking a discount, computing a tip, converting a test score, adjusting a recipe, or comparing two figures, the tool shows the result and the relationship behind it. Because it runs entirely client-side, it's fast and works offline once the page has loaded.

## FAQ

### How do I calculate what X% of a number is?

Enter the percentage and the total number. For example, 15% of 200 = 200 × 0.15 = 30. The calculator does this instantly as you type.

### How do I calculate percentage increase?

Formula: ((New Value - Old Value) / Old Value) × 100. For example, if sales went from $500 to $650: ((650-500)/500) × 100 = 30% increase. The calculator shows this automatically.

### How do I split a budget by ratio?

Enter your total budget and ratio (e.g., 60:40). The tool calculates the exact dollar amount for each part. A $10,000 budget split 60:40 gives $6,000 and $4,000.

### How do I calculate a discount percentage?

Original price: $80, Sale price: $60. Discount = ((80-60)/80) × 100 = 25% off. Or enter the original price and discount percentage to find the sale price directly.

### How do I calculate tip percentage at a restaurant?

Enter your bill total and the tip percentage (15%, 18%, 20%, etc.). The calculator shows the tip amount and total to pay. Standard tip is 15-20% for good service in the US.

### How do I find what percentage one number is of another?

Formula: (Part ÷ Whole) × 100. For example, if 30 students out of 120 passed: (30 ÷ 120) × 100 = 25%. Use the 'X is what % of Y' calculator mode to solve this instantly.

### How do I calculate a percentage increase?

Subtract the old value from the new, divide by the old value, and multiply by 100 — the tool does this automatically when you enter both numbers.

### How do I split an amount by ratio?

Enter the total and the ratio parts; the calculator divides the amount proportionally and shows each share.

---

ToolNova — free, privacy-first browser tools. Most tools process data locally on your device. See https://www.toolnova.org/llms.txt for the full directory.