Price Quantity Calculator

Background.

Revenue is the simplest number in business and the one most often mistaken for success. Sell 80 items at $12.50 and you have taken in $1,000, but if each item cost $7.50 in materials, packaging and payment fees, only $400 of that money is left to pay rent, wages and everything else that does not grow with each sale. That $400 is the contribution, and it is the figure that tells you whether the volume is doing any good.

Both numbers come from the same few facts, which is why it helps to see them side by side. Revenue is a rectangle: price along one side, quantity along the other. Contribution is a thinner rectangle cut from it, the gap between price and variable cost multiplied by the same quantity.

That gap is where pricing decisions bite. A discount comes entirely out of the margin on each unit, not out of the price as a whole, so a modest-sounding cut can remove a large slice of contribution. In the example below, a 10% discount wipes out a quarter of the contribution, and the seller would need a third more customers just to stand still.

The model is deliberately plain. It assumes one price for every unit and one variable cost per unit, and it takes the quantity as given: raising the price here does not make anyone buy less, though in a real market it usually does. Returns, volume discounts, taxes and fixed costs are not part of it, so contribution is not profit. It is the money available to cover fixed costs, and profit starts only once they are paid.

What is price quantity calculator?

Price-times-quantity revenue is the gross amount taken from sales before any cost is deducted: the unit price multiplied by the number of units sold. Contribution is that revenue minus the variable costs of the same units, meaning the costs that rise and fall with each additional sale, such as materials, packaging, per-order shipping or card processing fees. Fixed costs like rent and salaries are not subtracted, so contribution measures how much the sales add toward covering them.

How to use this calculator.

1. 01Enter Unit price as the amount customers actually pay per unit, after any standing discount but before sales tax, which you collect for the government rather than earn.
2. 02Enter Quantity sold for the period you care about: a day at a market stall, a month of online orders, or a planned production run.
3. 03Build Variable cost per unit from everything you spend because of one more sale: materials, packaging, shipping you cover, commissions and payment fees. Leave out rent, salaries and equipment, which stay the same whether you sell 80 units or 100.
4. 04Compare the two results. Contribution divided by revenue is your contribution margin ratio, and fixed costs divided by price minus variable cost is the number of units needed to break even.

The formula.

Revenue = P × Q and contribution = (P − V) × Q, where P is the unit price, Q the quantity sold and V the variable cost per unit. The bracket P − V is the unit contribution margin, what each sale adds after paying for itself. Both results share the factor Q, so doubling the quantity doubles both. Price acts unevenly, though: a $1 cut lowers revenue by $1 out of P per unit, but lowers contribution by $1 out of P − V, a much larger fraction when the margin is thin. If V exceeds P, contribution turns negative and every extra sale deepens the loss. Contribution divided by revenue gives the contribution margin ratio, (P − V) ÷ P, which does not depend on quantity at all.

A worked example.

Frequently asked questions.

References& sources.

1. [1]OpenStax, Rice University. Principles of Finance, 2022. Chapters 6–10. Retrieved 2026-08-06.
2. [2]U.S. Internal Revenue Service. Tax guidance current 2026. Official forms, instructions and tax topics. Retrieved 2026-08-06.
3. [3]U.S. Securities and Exchange Commission. Investor.gov current 2026. Investment products and risk. Retrieved 2026-08-06.