# Percentage, Margin and ROI Calculators

> Quick free tools for percentages, sale prices, profit margin, markup and return on investment, with the steps shown for each answer

Some questions are plain arithmetic, like what's 15% of a bill, how much is left after a sale, or how much profit hides in a price. These tools give you the answer and show you the steps.

The [percentage calculator](https://tax-services.ca/calculators/math-business/percentage-calculator) handles the usual cases, such as percent of a number, percent change and what percent one value is of another.

## Which tool for shoppers and owners?

Shoppers can use the [discount calculator](https://tax-services.ca/calculators/math-business/discount-calculator) to see a sale price and the amount saved. Sellers need the [profit margin and markup calculator](https://tax-services.ca/calculators/math-business/profit-margin-calculator), which converts between cost, price and margin. Investors can judge a return with the [ROI calculator](https://tax-services.ca/calculators/math-business/roi-calculator).

## How do I add tax and see the total?

Prices in Canada usually leave out sales tax. Add it with the [GST and HST calculator](https://tax-services.ca/calculators/sales-tax/gst-hst-calculator) and you'll see what you'll pay at the till.

Margin and markup aren't the same thing. A 50% markup gives a 33% margin, and that's why the tool shows both.

## When do these tools help?

Owners use them to set prices, buyers use them to judge a sale, and students use them to check homework. Each result shows its formula, so you can repeat the sum by hand if you don't trust a screen. Rounding follows normal rules, and dollar amounts show to the cent.

Comparing two offers? Work out the percentage difference, not the plain difference, because a $20 saving on a $50 item is far bigger than a $20 saving on a $500 one, even though the dollar figure looks the same. Your gut won't do that sum for you.

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Source: https://tax-services.ca/calculators/math-business
Last updated: 2026-10-01
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