A markup is the amount you add on top of what something costs you, expressed as a percentage of that cost. It’s how most people price a product or a piece of work day to day: take the cost, add a percentage, quote the result. This page walks through exactly how the markup calculator above turns a cost and a markup percentage into a selling price, and explains the one mix-up — markup versus margin — that causes more pricing errors than anything else. The output is an estimate based on the numbers you enter; it’s plain arithmetic you can check yourself.
How markup is calculated
The calculator uses two inputs: your cost and your markup percentage. From those it works out the selling price, the profit, and the equivalent profit margin.
Selling price = Cost × (1 + Markup% ÷ 100)
Once you have the selling price, profit follows directly:
Profit = Selling price − Cost
And because profit can also be read as a share of the selling price rather than a share of the cost, the calculator converts it into a margin too:
Margin% = (Profit ÷ Selling price) × 100
That last line is the one worth pausing on. Markup measures profit against cost. Margin measures the same profit dollars against selling price. Same numerator, different denominator — and that’s why the two percentages are never equal once there’s any profit at all.
A worked example
Take the calculator’s own default numbers: a cost of $100 and a markup of 50%.
Selling price: $100 × (1 + 50/100) = $100 × 1.5 = $150.
Profit: $150 − $100 = $50.
Now convert that profit into a margin: $50 ÷ $150 × 100 = 33.3%.
So a 50% markup on a $100 cost produces a $150 selling price, $50 of profit, and a 33.3% profit margin — not a 50% margin. Run those same figures through the calculator above and you’ll see the identical numbers: $150 selling price, $50 profit, 33.3% equivalent margin.
Markup vs margin: the mistake that costs people money
This is the single most common pricing error, and it’s easy to see why it happens — both numbers are percentages, both are derived from the same cost and profit, and people use the words “markup” and “margin” loosely in conversation. But they answer different questions:
- Markup answers: “How much am I adding on top of cost?” It’s profit ÷ cost.
- Margin answers: “What share of my selling price is profit?” It’s profit ÷ selling price.
Because selling price is always larger than cost (assuming you’re charging more than cost), dividing the same profit by the bigger number always gives a smaller percentage. That means markup is always a bigger number than margin for any profitable price. A 50% markup is a 33.3% margin. A 100% markup is a 50% margin. A 25% markup is only a 20% margin.
The practical risk: if a client, a spreadsheet template, or your own notes say “aim for a 40% margin” and you instead add a 40% markup, you’ll under-price the job and pocket less profit than you intended — the gap gets bigger the higher the percentage. The calculator shows both figures together specifically so you can catch this before you quote a price, not after.
What else affects your selling price
The formula above is fixed math — cost, markup, selling price and margin will always relate to each other exactly as shown. What changes the inputs you feed it is more situational:
- What counts as “cost.” Decide up front whether your cost figure includes only direct materials or also your time, overhead and shipping. A markup on a too-narrow cost understates what you actually need to charge.
- Market positioning. A markup that competitors or customers will accept depends on what else is available at similar quality and price.
- Volume and risk. Lower-risk, high-volume items can often carry a thinner markup and still produce healthy total profit; one-off or high-risk work usually needs a fatter markup to make sense.
- Target margin, not markup. If your actual goal is a specific margin (a common way to plan profitability), work backward: the markup percentage needed for a given margin is margin ÷ (1 − margin), both as decimals.
Plug your own cost and markup into the calculator at the top of this page, and check the margin figure it returns before you send a quote — it only takes a second to confirm you’re hitting the number you actually meant.