Short answer: Subcontractor bids on the same job vary widely — sometimes 5x or more — because each sub is pricing a different scope, a different level of risk, and a different appetite for your job. The biggest drivers are ambiguous or missing scope, different inclusions and exclusions, unknown existing conditions (especially in renovation), how badly the sub wants the work, and travel or mobilization costs. You shrink the spread by sending a trade-specific scope sheet and bid form, carrying allowances for unknowns, holding a site walk, leveling every bid line by line, and checking each number against an independent estimate.
It's one of the most frustrating moments in preconstruction. You send the same drawings to four subs and get back $150,000, $310,000, $480,000, and $1.2 million. Now what? Take the low number and hope? Average them? Call the high bidder and ask what they're smoking?
None of the above. A spread that wide is information. It's telling you the subs are not pricing the same job — and the fix is on the GC side of the table.
Why subcontractor bids vary so much: eight reasons
1. The scope is ambiguous or incomplete
If the drawings don't say exactly what's in a trade's scope — who provides blocking, who patches after the plumber, who carries temporary power — every sub fills the gaps differently. The cautious sub prices everything. The hungry sub prices the minimum and plans to change-order the rest.
2. Inclusions and exclusions differ
Read the fine print on the low bid. "Excludes permits, testing, cleanup, patching, prevailing wage, after-hours work, and anything not shown." The high bidder included all of that. On paper, they bid different jobs.
3. Existing conditions are unknown
In renovation, historic, and adaptive reuse projects, nobody knows what's behind the walls. One demolition or abatement sub assumes the drawings are right; another assumes the worst and prices it. Structural surprises, hazardous materials, and out-of-plumb framing all widen the spread.
4. Some subs don't want the job
A sub who's booked solid for six months may send a "go away" number rather than decline. It keeps the relationship alive without committing crews. These bids are often the highest in the set.
5. Travel, mobilization, and market distance
In small towns and new markets, the nearest qualified sub may be two hours away. Their number includes drive time, per diem, and multiple mobilizations. A local sub doesn't carry those costs.
6. Risk pricing for an unknown GC
Subs who don't know you price in the risk that you'll pay slow, run a messy site, or shop their number. See how to find subcontractors in a new market for how to earn the local price.
7. Missed addenda or wrong drawing set
One sub bid addendum 2, another bid the original set. It happens more than anyone admits, especially when plans are emailed around rather than posted in one place.
8. Honest mistakes
Wrong unit, missed floor, a takeoff on the wrong scale. If one bid is wildly low compared to the rest, it's often a takeoff error — and awarding it will cost you when the sub tries to recover.
How to shrink the spread before bid day
Send a trade scope sheet, not "per plans and specs"
For each trade, list what's included, what's excluded, which sheets and spec sections apply, and who handles the common gray areas. It takes an hour and saves days of leveling. Our subcontractor scope of work template is a starting point.
Use a bid form with the same line items
Ask every sub to price the same breakdown: base scope, alternates, unit prices, and the exclusions they're taking. When everyone fills in the same form, the differences jump off the page.
Carry allowances for unknown conditions
For renovation work, don't make subs guess. Define an allowance ("carry $40,000 for concealed structural repairs") or a unit price ("per LF of rotted sill plate replaced"). Everyone prices the same known scope, and the unknown is handled in the contract.
Hold a pre-bid site walk
Especially for existing buildings. Subs who've seen the conditions price them more tightly — and the ones who didn't show up are telling you something.
Level every bid line by line
Put the bids in one grid by scope item. Where a sub excluded something, plug in a number (from another bid or your estimate) so totals are comparable. Then call each outlier with specific questions. We walk through the process in bid leveling in construction.
Benchmark against an independent estimate
The only way to know whether $150K or $1.2M is closer to right is to have your own number. If you don't have an in-house estimator, an AI takeoff and estimate gives you a trade-by-trade benchmark before the bids come in. Our roundup of AI estimating software for GCs compares the options.
Get enough bids to see the real market
Two bids is a coin flip. Aim for three or more per trade. If one comes back far below the others, call to confirm scope before you celebrate. And if the low bidder is a sub you've never used, run the same checks you'd use to vet an out-of-state subcontractor before you award.
How Struvia narrows bid spreads
Struvia builds the pieces above into one workflow:
- An AI takeoff and estimate for each trade, so you have a benchmark before bids arrive.
- Trade bid packages with scope sheets, sent to matched subcontractors in the project's area.
- Follow-up by email, text and phone, so more of the subs you invite actually bid and you have enough numbers to see the real market.
- Bid leveling that lines up each sub's inclusions and exclusions against the scope and against the estimate, and flags what's missing.
The result: you see why the numbers differ, not just that they do. Try it on one project.
Frequently Asked Questions
Is it normal for construction bids to vary by 5x?
In our experience, spreads of 10–30% are common on new construction with clear drawings. Spreads of 3–8x usually mean the scope is unclear, conditions are unknown (renovation), or at least one sub doesn't want the job.
Should I take the lowest subcontractor bid?
Only after leveling. The lowest bid is often low because it excluded scope that the others included. Confirm scope in writing before awarding.
What do I do when I only get one or two bids?
Widen your invite list and radius, fix anything unclear in the scope sheet, and follow up by phone. Use an independent estimate to sanity-check the bids you have.
How do I handle unknown conditions in renovation bids?
Use allowances or unit prices for concealed conditions so every sub prices the same known scope, and hold a pre-bid site walk.
*Reviewed by Baylor Jeppsen, Construction Estimating Expert and Founder of Struvia.*
