Markup vs margin: the difference that costs money at discount time

A 50% markup is a 33.3% margin, not 50%. Here is the conversion, and the arithmetic that shows why discounting hurts more than most people expect.

By X Centrix AIPricing & Profit5 min readPublished 3 October 2026

Two percentages that share a numerator and differ in the divisor

Markup and margin are both the profit on a sale divided by something. The only difference is what that something is, and that difference is where the money goes missing.

Markup = (price − cost) ÷ cost
Margin = (price − cost) ÷ price

Both are legitimate. Markup answers a pricing question — what did I add on top of my cost? Margin answers a profitability question — what share of this sale did I keep? Mixing them up answers neither.

A 50% markup is a 33.3% margin. This is not a rounding difference; it is a third of the margin, gone, in a single sentence.

The conversion, and the table worth keeping

Margin = markup ÷ (1 + markup). The reverse is markup = margin ÷ (1 − margin). Both are one line, and between them they remove the entire problem.

Markup	Actual margin
10%	9.1%
20%	16.7%
25%	20.0%
33%	25.0%
50%	33.3%
75%	42.9%
100%	50.0%
200%	66.7%

Read the bottom line twice. Doubling your cost gives you a 66.7% margin, not a 100% margin. There is no markup percentage that produces a 100% margin, because margin's divisor is the price and the cost can never reach zero.

Why the confusion survives anyway

The two terms come from different rooms. Pricing teams talk in markup, because they build up from cost. Accounting and investors talk in margin, because it is the ratio that survives across products of different sizes.

Both groups say percent. Neither group says which percent. That is the entire problem, and it is why the same deal gets described as a 50% deal by the person who priced it and a disappointing 33% deal by the person reading the accounts.

Where it actually costs money: discounting

Margin confusion is survivable until someone discounts. Discounts come off the price, but the cost does not move — so every percentage point of discount comes directly out of profit, on a base that is already smaller than the price.

Take a product that sells for $100 with a cost of $70. Profit is $30, a 30% margin. Now discount 20%.

New price: $80
Cost: still $70
New profit: $10
Profit change: $30 → $10, a fall of 67%

A 20% discount took two thirds of the profit. A 30% discount would have sold it at cost — full revenue, zero profit, and it would still have looked like a healthy sale in the revenue report.

Pricing from a target margin rather than a cost-plus habit

To hit a target margin, divide cost by (1 − target), rather than multiplying cost by (1 + a markup you guessed at).

A $70 cost at a target 30% margin needs $70 ÷ 0.7 = $100. If you had reached for a 30% markup instead, you would have priced it at $91 and quietly missed the margin by a sixth.

Target margin	Multiplier on cost	Price for a $70 cost
20%	1.25×	$87.50
30%	1.43×	$100.00
40%	1.67×	$116.67
50%	2.00×	$140.00
60%	2.50×	$175.00

The largest discount you can give before you hit your floor

Once you know the price that produces your floor margin, the maximum discount stops being a matter of nerve and becomes arithmetic:

Cost	Floor margin	Floor price	Room from a $100 list
$70	20%	$87.50	12.5% discount
$70	25%	$93.33	6.7% discount
$70	30%	$100.00	none — the list price is the floor
$60	20%	$75.00	25.0% discount

Read the third row twice. At a $70 cost and a 30% floor margin, the list price of $100 is the floor — there is no discount available at all, and every percentage point offered comes straight out of margin rather than out of waste somewhere else.

The fourth row is the useful one. A lower cost buys discount room without touching the margin. Negotiating a better supply price is often a better route to winning a price-sensitive deal than cutting the price and hoping volume covers it.

Work the floor out once per product and write it down. Deciding it in the room, against a buyer who is asking, is how floors get crossed.

The deeper problem with cost-plus pricing

Everything above assumes cost-plus pricing is the right approach. It has a known failure: it prices your work according to what it cost you, not according to what it is worth to the buyer. On a high-value problem, a cost-plus price leaves money on the table; on a commodity, it prices you out.

Margin discipline matters most precisely where cost-plus is weakest. Knowing your margin tells you the floor — the price below which the work stops being worth taking — and that is a different and more useful number than the price you would like to charge.

Check any price in a few seconds

The Margin Calculator converts between markup and margin, solves for the price that hits a target margin, and shows what a discount does to profit before you agree to it rather than after.

Frequently asked questions

Is markup always higher than margin?

Yes, for any positive profit. Margin's divisor is the larger number — the price — so margin is always the smaller percentage. They are equal only at zero profit, where both are zero.

Why is 100% margin impossible?

Margin is profit divided by price, and profit is price minus cost. To reach 100% the cost would have to be zero. A 100% markup, meanwhile, is merely a 50% margin — which is where most of the confusion starts.

How do I know if a discount is safe?

Check the profit, not the price. Work out profit at the discounted price and cost unchanged, then compare it with your target. If the discounted profit falls below your floor, the deal is not a discount, it is a decision to buy revenue.

Does a high margin mean a healthy business?

Not on its own. Margin says what each sale keeps; it says nothing about how many sales there are, or what it cost to acquire them. A 60% margin on ten sales is not obviously better than a 30% margin on a thousand.

Spotted something wrong in these numbers? Tell us — corrections are the fastest thing we ship.