# Discount Calculator - % Off, Sales Tax, Margin, Markup & Tip

> Free discount calculator: sale price after % off and stacked discounts, spend-and-save deals, deal and unit price comparison, margin, markup, sales tax, tips.

- URL: https://qilingtools.com/en/math/discount
- Category: Math Tools (https://qilingtools.com/en/math)
- Tags: [Math](https://qilingtools.com/en/tags/math), [Finance](https://qilingtools.com/en/tags/finance), [Everyday Life](https://qilingtools.com/en/tags/life)
- Last updated: 2026-10-26
- Price: Free, no sign-up
- Privacy: Runs locally in the browser; files are never uploaded

The everyday business and shopping percentages in one place: what 20% off and then another 10% off really costs and the equivalent single discount; what you pay after a “spend 300 save 50” tier and a coupon, and how much more you need to reach the next tier; whether “20% off”, “spend 150 save 40”, “buy 2 get 1 free” or “second item half price” is the better deal; which pack size is cheaper per 100 g or per ounce; the margin and markup of an item that costs 80 and sells for 100; the percentage change from 80 to 100; the tax inside a price that includes 20% VAT; and the tip and each person’s share of a restaurant bill. Every result shows its formula and the usual pitfalls, such as stacked discounts multiplying rather than adding.

## How to use

1. Choose a tab: discount price, spend & save, compare deals, unit price, margin vs markup, % change, sales tax or tip
2. Enter the price and the discounts, tiers, tax rate or tip percentage
3. Read what you pay, what you save, the equivalent discount and the formula; the best option is highlighted

## Features

- Stack several % off discounts and see the equivalent single discount
- Work backwards from the original and sale price to the discount you got
- Spend-and-save tiers (best tier or repeating per amount) plus coupons, with a “spend X more” hint
- Compare deals by unit price and quantity: % off, spend & save, flat amount off, buy X get Y free, Xth item discounted
- Unit price comparison with g, kg, lb, oz, ml, L, fl oz and gallon conversion
- Gross margin ↔ markup, and the selling price for a target margin
- Percentage increase / decrease and reversing a percentage change
- Tax-inclusive ↔ tax-exclusive prices (VAT / sales tax) and tip splitting

## FAQ

### Is 20% off plus another 10% off the same as 30% off?

No. Stacked discounts multiply: 0.8 × 0.9 = 0.72, so you pay 72% of the price — a 28% discount, not 30%. Enter “20%, 10%” in the discount tab to see the price after each step and the equivalent single discount.

### What is the difference between margin and markup?

Margin is profit divided by the selling price; markup is profit divided by cost. An item that costs 80 and sells for 100 makes 20 profit: a 20% margin but a 25% markup. For a 30% margin the price must be cost ÷ (1 − 0.30), not cost × 1.3.

### How do I remove sales tax or VAT from a price?

Divide the tax-inclusive price by 1 + the tax rate: 120 including 20% VAT is 120 ÷ 1.2 = 100 before tax, so the tax is 20. Multiplying 120 by 20% (24) overstates the tax. To add tax, multiply the net price by 1 + the rate.

### How much should I tip, and should it be on the pre-tax amount?

In the US 15–20% of the pre-tax bill is standard at sit-down restaurants and 20–25% for excellent service. Tick “tip on the pre-tax amount” and enter the tax shown on the receipt to exclude it, set the number of people to split the bill, and optionally round each share up to a whole amount.

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