Markup isn’t margin.
If a job costs $100 and you add 30%, the price is $130. Your profit is $30 — but your margin is 23.1%, not 30%.
They divide by different numbers.
Markup = profit ÷ cost. In this example, $30 ÷ $100 = 30%.
Margin = profit ÷ selling price. Here, $30 ÷ $130 = 23.1%.
Work backward from a target margin.
Without payment fees, a price that targets 30% margin on $100 of costs is $100 ÷ (1 − 0.30) = $142.86, rounded to cents. The profit is approximately $42.86.
Include the costs the job really uses.
Start with person-hours multiplied by labor cost per hour. Add materials, travel, allocated overhead and other job costs. Include a value for your own labor so that unpaid work does not make the margin look stronger.
Account for processing fees.
If the processor charges a percentage of revenue plus a fixed fee, the price before tax is:
For $100 of costs, a $0.30 fixed fee, a 2.9% percentage fee and a 30% target margin, the result is $149.48, rounded upward to cents. These rates are fictional illustrations, not a recommendation or a current processor quote. The denominator must stay above zero.
Discounts need room in the list price.
A 10% discount on a $100 price removes $10 from revenue. If costs stay the same, the entire $10 comes out of profit. To preserve a planned final price, divide it by 0.90 before rounding the list price.
Then compare the estimate with the actual job.
Record actual labor hours, materials, fees and revenue. A price calculator can only be as accurate as its inputs. It cannot establish what a customer will pay or guarantee a profitable business.
All examples are in USD, before sales tax. This guide explains spreadsheet arithmetic; it does not calculate taxes or replace professional accounting advice.