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$2,800/wk × 16 weeks = $44,800 of GCs on a $500k job — 9.0%. GCs are time-driven, not value-driven: a gut-feel percentage under-prices every long thin job.
General conditions are the bid line contractors feel instead of measure. The honest build: supervision $2,000/wk loaded, trailer and utilities $400, fence and toilets $150, insurance $250 — $2,800 per week, times 16 weeks, equals $44,800 on a $500,000 contract: 9.0%, not the 7% the gut said. And because GCs run on the calendar, schedule slip is a priced event — four unpriced weeks is $11,200 straight off margin. This calculator builds the weekly rate from your actuals and loads the bid with it — the same weekly figure your change orders and delay claims should be quoting.
Estimators use it before bidding: $2,800/wk × 16 weeks is $44,800 of GCs (9% of contract) — GCs run on the calendar, so a gut-feel percentage under-prices every long thin job and every week of slip.
The split that under-prices both when mixed: GCs are JOB costs — things that exist because THIS project exists: the superintendent and their truck, the job trailer and its utilities, temporary fence/toilets/power, project-specific insurance (builder's risk, project GL), permits and fees, small tools and consumables, job-specific safety program costs, winter conditions, cleanup labor. Company overhead is OFFICE costs — things that exist whether or not this job does: rent, admin staff, estimating, software, the owner's salary, marketing — recovered through the markup on the whole bid. The test: "does this cost disappear the day this job ends?" Yes → GCs. No → overhead. The common leaks: the super's loaded wage (burden adds 30–50% — the labor-burden calculator builds it), insurance riders bought per project, and the pickup truck that is half job-cost half company. Get the split right and both numbers become auditable: GCs per week from job records, overhead rate from the P&L. Mixing them is how a contractor "wins" bids that lose money.
Because GCs run on the calendar, not the ledger — supervision and the trailer cost the same in a $40,000 production week as a $400,000 one. A flat percentage therefore misprices every job that is not average: long, thin jobs (extended schedule, modest monthly billings) get under-priced — the percentage was tuned on faster jobs and the extra weeks eat the margin; short, fat jobs get over-priced — which loses bids you should win. The weekly build also makes slip a number: when the schedule extends four weeks, the cost is weekly GCs × 4 — knowable in advance, claimable with documentation, and the exact daily/weekly figure that belongs in change-order pricing (the change-order calculator applies it) and in any delay claim. The calibration loop: after each job closes, divide actual GCs by actual weeks and compare to the bid rate — two or three closed jobs tune your weekly number to reality. The percentage check still has a role: divide the itemized total by contract value and compare against your historical range — if itemized says 9% and history says 6–7%, either the schedule is optimistic or a line is padded. Itemized for the bid, percentage for the sanity check.
They are the whole claim — which is why the weekly number must exist before you need it. Change orders with time impact: every added day of schedule carries the daily GCs rate (weekly ÷ working days); the change-order calculator builds the price as direct cost plus OH&P plus extension days × GCs rate — owners instinctively treat time as free, and the itemized weekly build is the evidence it is not. Delay claims: when the owner or another party delays the job, the compensable damage is extended GCs — your trailer, your supervision, your insurance running extra weeks — and claims live or die on whether you can document the weekly rate from job records rather than reconstructing it for litigation. The contractual protections: a defined GCs rate or schedule in the base contract (negotiated when everyone is friendly), written time-impact statements on every change order (even "zero days," so float erosion cannot be relitigated), and contemporaneous records — daily reports and cost records kept DURING the job, not assembled after. Contractors who can produce the weekly number from job costs settle delays at the table; contractors who reconstruct it settle at a discount. This calculator builds the number; the field records defend it.