Start with the denominator
A percentage only becomes meaningful when you know what it divides by. Margin is profit divided by the selling price. Markup is profit divided by cost. If a job costs 12,000 currency units and sells for 16,000, the 4,000 difference is a 25% margin and a 33.33% markup. Both statements describe the same scenario; they are not interchangeable instructions.
Build a consistent cost base
List direct labour, materials, subcontractors and the overhead that this job must recover. Check whether employer costs, transport and equipment have already been included elsewhere. A target margin applied to an incomplete cost base will not recover the missing costs. Keep tax-inclusive and tax-exclusive figures separate, and ask your accountant which costs are recoverable in your circumstances.
Test the price before agreeing it
Use the markup-versus-margin calculator to compare the two percentages. Then test a second scenario with a realistic change in cost. Save the assumptions with the estimate. A calculated target price is a planning aid: market conditions, the scope, risk and signed contract terms still affect what you can charge. No example margin on this site is presented as an industry benchmark.
On your side of the Atlantic
Use your state and local sales-tax treatment, payroll records, and supplier quotes. A national default cannot describe every US job.
Open calculator ↗Planning estimate only. Not a substitute for a professional quote or local building-code compliance. Verify quantities, tax treatment and contract requirements.