Plug Number

A plug number is a placeholder cost dropped into an estimate when the real figure is not available yet — “plugged in” to keep the estimate complete, flagged to be replaced before the bid goes out.

Plug numbers are useful during early pricing when vendor quotes, owner selections, or design details are still pending.

They become dangerous when they are forgotten. Clear flags, owner notes, and bid-day checklists keep plugs from shipping as firm pricing.