Why the subcontractor margin calculator matters
Subcontracting scales revenue faster than headcount but it also transfers all the warranty and schedule risk onto you, which is exactly what the margin is paying for. This page turns that decision into a handful of inputs you can defend in a budget review: volume, unit cost, rate of adoption, and time. The output is a planning baseline, not a promise — it tells you whether the idea deserves a vendor quote, a pilot, or a pass.
- • Biggest swing factor: your markup on subbed labour
- • Second-order factor: callback and rework rate, which eats margin invisibly
- • Often ignored: management overhead, which grows with the number of subs
What actually changes the answer
your markup on subbed labour moves this number first, then callback and rework rate, which eats margin invisibly. Run a conservative case and an upside case before you commit. If the maths only works in the upside case, treat it as a time-boxed test with a kill date rather than a line in next year's plan.
What to do with the result
Track callbacks by sub for a quarter and drop anyone whose rework wipes out the markup on their jobs.
FAQ
What does the subcontractor margin calculator work out?
It applies Extra conversions = volume × base rate% × lift%; Value = extra conversions × value each; Net = value − cost to the values you enter for subcontracted job value per month ($), your gross margin on subbed work, extra margin from managing it well, average value of one job ($), monthly cost of managing subs ($). Subcontracting scales revenue faster than headcount but it also transfers all the warranty and schedule risk onto you, which is exactly what the margin is paying for.
How accurate is this subcontractor margin calculator?
A margin model, not a job-cost system. Retainage, lien risk and payment timing are not modelled. Replace the defaults with your own invoice, usage export, payroll data, statement, or vendor quote before making a commitment — the maths is exact, so the answer is only as good as the inputs you feed it.
Which input should I stress-test first?
your markup on subbed labour. Re-run with a pessimistic value for it; if the decision flips, that assumption is the thing you need real data on before signing anything. After that, check callback and rework rate, which eats margin invisibly and management overhead, which grows with the number of subs.
Which scenario should I start from?
Start with the preset closest to your situation — soft demand, current numbers, strong demand — then edit the sliders. Presets are realistic starting points, not benchmarks to match, and every change updates the result instantly.
What should I do after running the numbers?
Track callbacks by sub for a quarter and drop anyone whose rework wipes out the markup on their jobs. A useful planning benchmark to compare against: Trade contractors commonly mark subbed work up 15–25%, and callbacks are what erase it.
Can I share or save this calculation?
Yes. Your inputs are written into the page URL, so copying the link shares the exact scenario you are looking at — the person who opens it sees the same numbers. You can also export the inputs and results to CSV or PDF from the result card and keep it with the rest of your workings.
How this calculator is built
Independently maintained
Written by Sam Doshi and the RevenueLab editorial team. We don't sell the data feeds this tool is built on.
Sourced from primary data
Benchmarks come from public AdSense / Stripe / IRS disclosures and reader-submitted data — never third-party "$X per view" claims. Full methodology.
Last editorial review
Reviewed on a rolling quarterly cycle. Dated reviews are published on the methodology record for each calculator.
Editorial standards
See our editorial policy and disclaimer. Results are estimates, not advice.