How many subcontractors should you invite to bid?
The arithmetic for landing four to six real bids per trade, a per-scope target table, why over-inviting quietly loses you the subs you want, and when to go above or below the numbers.
"Invite everyone" sounds like a strategy. More invitations, more bids, lower number. In practice it produces fewer good bids, and the arithmetic doesn't support it either. Here's how to set targets per scope.
Start from the bids you want
On a major trade you want four to six real, leveled bids. Fewer than three and you don't know the market price. More than six and you spend bid day leveling numbers you'll never use. On minor trades, two or three. On some specialties you'll be glad to get one.
So the question is: how many do you need to invite to land five?
The conversion arithmetic
With a healthy response rate of 70 percent, roughly 60 percent of responders saying "bidding," and about 85 percent of those delivering a number:
Invite 10 → 7 respond → 4 say bidding → 3 or 4 bids.
To land five bids at those rates, invite 12 to 14. At a 40 percent response rate, the same target needs 22 to 25. Estimators with weak processes invite 40 and still end up with three bids. They're right that they need to invite more; they're solving the wrong problem.
Why over-inviting costs you bids
Good subcontractors talk to each other and they can count. When a strong drywall contractor knows you've invited thirty firms, their odds are worse than one in ten even if they bid well. A proper estimate on a $400,000 scope takes two or three days of a senior estimator's time. At those odds the good ones pass, and the bidders left in are the ones with nothing better to do.
Invite eight, tell them so, and the same contractor sees a real chance and puts real effort in. Fewer bids, better bids, and the good subs learn your invitations are worth reading.
Ask any experienced sub estimator how they triage invitations. "How many others are on it" is in the top three questions.
Per-scope targets
For a mid-size commercial job with a healthy response rate. For reference, ConstructConnect's published guideline is 5 to 8 invitations per trade to get 3 to 5 proposals, assuming 30 to 50 percent of invited subs don't respond. Adjust for your market.
| Scope | Bids wanted | Invite |
|---|---|---|
| Mechanical, electrical, plumbing | 4 to 5 | 6 to 10 |
| Drywall, concrete, structural steel | 4 to 5 | 6 to 10 |
| Roofing, glazing, masonry | 3 to 4 | 6 to 8 |
| Flooring, painting, tile, ceilings | 3 | 5 to 6 |
| Millwork, doors and hardware, specialties | 2 to 3 | 4 to 5 |
| Elevators, fire suppression, fire alarm | 2 to 3 | 3 to 5 (often the whole market) |
| Site work, landscaping, paving | 3 | 5 to 6 |
If those look low compared to what you do now, that's the point. If they look high, your list is thin in those trades; work on it between bids, not during one.
When to invite more
- New market. Invite wider on the first two jobs, note who performs, then narrow.
- Hot market. "Bidding" conversion drops. Check counts on day 8 and add invitations then, to named firms.
- Unusual scope. Half your list will decline, so cast wider.
- A trade where you've been burned. If the last three drywall bids came from the same two firms, add three new names and tell all of them there are six on it.
The common thread: invite more deliberately, for a reason, to named firms. Not "select all."
When to invite fewer
- Negotiated or repeat work. Two or three bids for price validation is plenty.
- Short bid periods. Inviting fifteen doesn't create capacity; it creates fifteen emails.
- Small specialty markets. Three elevator companies will bid your job. Inviting three is inviting everyone.
Check the count halfway
Whatever you invited, the number that matters on day 8 is how many have said "bidding" per scope. Under three on a major trade: widen the region, ask a trusted sub for a referral, phone the two you most want. The worst outcome isn't inviting too few. It's inviting the right number, not tracking responses, and discovering on bid day that you have one mechanical price.
That per-scope count is why response tracking matters. Invite All (our product) shows it live per scope ("electrical: 4 bidding, 2 maybe, 3 silent"); a spreadsheet with a status column and a pivot table gives the same number with more effort. Look at it on day 8, not day 20.
Short version
Aim for four to six bids on the trades that matter. Invite roughly double that from a clean list, personally, and tell them how many are on it. Fix response rate before widening the list. Check the count halfway through.