Margin and markup are different.

Both describe the relationship between price and cost. They use different starting points, and that changes the answer.

Markup starts with cost.

Markup is profit divided by cost. If a job costs $100 and you add 20%, the selling price is $120 and the profit is $20. That is a 20% markup.

Margin starts with the selling price.

Margin is profit divided by revenue. On that same $120 job, $20 ÷ $120 = 16.7%. A 20% markup therefore produces about a 16.7% margin before any additional fees.

Payment fees change the equation.

If your payment provider charges 3% of the selling price, and your cost is still $100, the price for a 20% margin becomes $100 ÷ (1 − 0.03 − 0.20) = approximately $129.87. If a fixed fee also applies, add that fee to the numerator before dividing.

Decide what belongs in “cost.”

For a solo detailer, include your own pay allowance as well as supplies, travel expenses, and allocated overhead. Otherwise a number labeled “profit” may still need to pay you for the hours you worked.

A target is a planning choice.

The calculator can work backward from a margin target. It cannot tell you that customers will accept the resulting price or that you will achieve the margin. Actual time, scope changes, discounts, missed costs, and fees can all change the result.

Examples use USD and exclude sales tax, income tax, and unlisted costs. Rounding a price up may slightly increase the resulting margin.