Definition
A plug number is a temporary dollar figure a general contractor drops into its estimate for a scope package where no firm subcontractor bid has arrived yet. Heavy-civil work runs on a clock: the GC has to deliver a complete number, but the electrical, signal, or landscaping subs may not get their quotes in until the last hours before the deadline. Rather than leave a hole, the estimator plugs a reasonable allowance — based on prior jobs, square-foot history, or a quick budget pricing — so the rolled-up total is whole and the bid can go out on time.
The plug is always meant to be replaced. Once real sub bids land for that package, the GC levels them, picks a number, and swaps the placeholder out for the leveled figure. A plug that never gets reconciled is a liability: it either pads the bid and loses the job, or hides a gap that surfaces later as a cost overrun. The discipline is knowing which line items are still plugs and chasing every one to a real, scoped number before award.
A worked example
You are assembling a roadway package and every trade has quoted except electrical. With two hours left, you carry a $400,000 plug for the electrical scope, pulled from a similar interchange job last year, so your bid total holds at $8,650,000 and goes out clean. The next day the real electrical bids arrive: Sub A at $372,000, Sub B at $418,000, and Sub C at $361,000. After leveling them to your scope — adding back the conduit Sub C omitted — Sub A is the lowest responsible number at $372,000. You swap the $400,000 plug for the leveled $372,000, and your carried estimate drops by $28,000. Had you instead plugged $340,000 and won, that $32,000 gap would have come straight out of margin.
Why it matters when you evaluate sub bids
A plug number is a placeholder, not a bid — and the moment real sub bids come in, the plug is exactly what you are testing them against. If the field clusters well below the plug, you carried too much and may have left the job on the table; if every bid lands above it, the plug was optimistic and your margin was never real. Either way, the plug has to be retired and replaced with a leveled, scope-equalized number before you commit. Treating an unreconciled plug as if it were a firm price is how change orders and busted budgets start. Clean evaluation means tracking every plugged package, leveling the bids that come in, and awarding off the real number — not the placeholder that held the estimate together.
How Bid Reasoner handles it
Bid Reasoner is built for the second half of that story — the bids you receive once the plug needs replacing. It reads each electrical bid PDF, normalizes every line item to your scope of work via peer-median normalization (no government data required) so it works in any US state, and scores the field across all six dimensions: price, scope, schedule, compliance, performance, and risk. Two-way scope-coverage gap analysis catches the conduit Sub C left out, with page-cited evidence quotes, and the four deterministic risk rules flag any unbalanced unit price at or under $1.00, peer outlier above 2x or below 0.5x the peer median, total-bid outlier beyond 20%, or front-loaded mobilization over 10% of total. You pick a decision mode, get the leveled award number, and swap it in for the plug with an audit trail behind it.