How to Use the Cost, Price & Margin Calculator
This calculator takes exactly two of the three values โ cost, selling price, and margin rate โ and instantly solves for the missing one. It's built for small business owners and online sellers who need to answer questions like "I know my cost and target margin, what should I charge?" or "If I sell at this price, how much margin am I actually making?"
The margin rate here is calculated on the selling price: (selling price - cost) รท selling price ร 100. This is a different concept from markup, which is calculated on cost โ mixing the two up is a common and costly mistake. For example, a $70 item sold at $100 has a 30% margin, but its markup is about 42.9%, a meaningfully different number.
If the margin rate is entered as 100% or higher, the math implies a cost or selling price of zero or less, which is impossible โ the calculator flags this automatically. Fill in exactly two values and the third updates instantly, making it easy to compare several pricing scenarios quickly.
Frequently Asked Questions
This calculator computes margin on the selling price: (selling price - cost) รท selling price ร 100. This differs from markup, which is calculated on cost, so be careful not to confuse the two.
This calculator only reverse-calculates the missing value when exactly two fields are filled in. If you fill in all three, or only one, it's unclear which value to solve for, so a guidance message appears instead of a result.