# A percentage calculator you type in plain words

Written 18 October 2026 by Adrian Viziteu. Every example was run through Ratio 0.6.4 that day.

Is it 20% of the price, 20% off, or 20% on top? Percentages trip everyone up. In Ratio, you write the question the way you'd ask it, and the answer appears right beside it.

## The everyday percentages

| 20% of 150 | 30 |
| --- | --- |
| 150 + 20% | 180 |
| 150 - 10% | 135 |
| 12% of 3,400 | 408 |

## What percent is it?

Ask for the share, the whole, or the change between two numbers.

| 50 is what % of 200 | 25% |
| --- | --- |
| 30 is 15% of what | 200 |
| change(80, 100) | 25% |
| change(100, 80) | -20% |

## Discounts and tips

Name a value once and reuse it on the next line. Change the bill and the tip follows.

| 49.99 - 25% | 37.49 |
| --- | --- |
| 120 is 20% off what | 150 |
| tip = 18% of 64 | 11.52 |
| 64 + tip | 75.52 |

## Margins, markups and VAT

Margin and markup are different percentages of the same two prices. Ratio has both, and adds or removes VAT at your region's rate. More in the [VAT calculator](https://useratio.app/vat-calculator) guide.

| margin(80, 100) | 20% |
| --- | --- |
| markup(80, 100) | 25% |
| 80 + 25% margin | 106.6667 |
| 1000 + VAT | 1,190 |

[Try Ratio free for 7 days](https://useratio.app/download) · $9.99 once, on Mac, Windows and Linux

## Questions

**How do I calculate a percentage of a number?** Type it in words, like `20% of 150`. Ratio shows 30 next to the line.

**How do I find what percent one number is of another?** Write `50 is what % of 200`. The answer is 25%.

**How do I calculate percentage change?** Use `change(80, 100)` for the change from 80 to 100, which is 25%. From 100 to 80 it is -20%.

**How do I find the original price before a discount?** Write `120 is 20% off what`. The price before the discount was 150.

Source: https://useratio.app/percentage-calculator