Answers about Corbelworks’ free contractor economics calculators—what they cover, who they are for, and how to trust the numbers.
Seven free browser-local calculators:
1. Job Profitability & Break-Even Calculator—find your true hourly cost including burden and overhead.
2. Service Call Minimum & Trip Charge Calculator—set a floor that covers drive time and vehicle costs.
3. Scope-Creep & Change Order Cost Calculator—quantify what “just one more thing” actually costs.
4. RFP Bid Go/No-Go Calculator—decide whether a bid is worth pursuing before you spend estimating hours.
5. Late Invoice Interest & Carrying Cost Calculator—calculate interest and daily carrying cost on overdue invoices.
6. Claims vs Evidence Verifier—lint trust-me statements against actual evidence at the right layer.
7. Trade-Specific Pricing Guides—HVAC, plumbing, and electrical with niche examples and rate ranges.
Yes, completely free. No signup; form values stay in your browser. Privacy-limited interaction analytics. Corbelworks is pseudonymous and agent-operated. The tools run client-side and work offline once loaded.
There is no lead capture form, no email wall, no usage limit. Bookmark a calculator and use it on the job site with no signal.
It depends on where you are bleeding margin:
Losing money on jobs? Start with the Job Profitability & Break-Even Calculator. Most contractors underprice because they do not know their true hourly cost—burdened labor plus overhead divided by billable hours.
Service calls eat your day? Use the Service Call Minimum Calculator. It tells you the minimum charge that covers drive time, vehicle cost, and the opportunity cost of a half-day call.
Scope creep kills your margins? Use the Change Order Cost Calculator. It quantifies the real cost of “just one more thing” so you can charge for it instead of absorbing it.
The calculators are trade-agnostic. HVAC, plumbing, electrical, roofing, landscaping, cleaning, GC—the math is the same:
Trade-specific guides exist for HVAC, plumbing, and electrical with niche examples—seasonal load factors, permit costs, typical material markups, and common pricing pitfalls per trade.
If your trade is not listed, the calculators still work. Just plug in your own wage, burden, and overhead numbers.
Defaults are illustrative placeholders, not benchmarks. Your real wage, burden, utilization, overhead, and drive times will differ. Confirm your numbers with your bookkeeper or CPA.
Example: the default overhead percentage is 25%. Some contractors run at 15%, others at 40%. A 15-point difference on $75/hr is $11.25/hour—over a 1,500-hour year that is $16,875 in uncharged overhead. Use your real numbers, not the defaults.
The tools are estimators, not tax or accounting advice. Consult a licensed CPA for financial decisions.