If you've been in construction long enough, you already know this scenario: you're reviewing the bid documents, cross-checking the plans against the specifications, and suddenly the numbers don't line up. The drawings say 1,200 square feet of drywall. The specs say 1,450. The quantity takeoff sheet says something else entirely. Now what?
Conflicting quantities in bid documents are one of the most common and most costly problems contractors and estimators run into. Get it wrong, and you either underbid the job and eat the loss, or overbid it and lose the contract to someone who read the discrepancy differently. Neither outcome is good. So let's talk about what's actually going on when this happens, and what you should do about it.
Common Causes of Quantity Discrepancies in Construction Bids
Before jumping into solutions, it helps to understand why this keeps happening on projects, even well-managed ones.
Multiple authors, multiple documents. Architects draw the plans. Structural engineers issue their own set. MEP consultants add theirs. Specifications are often written by a separate team, sometimes using boilerplate language that doesn't get fully updated for the specific project. When five different people are contributing to one bid package, inconsistencies are almost inevitable.
Revisions that don't fully propagate. A design gets updated late in the process maybe the owner asked for a larger conference room and the drawing gets revised, but the specification narrative or the quantity schedule doesn't get updated to match. Now you've got two "official" numbers that used to agree and no longer do.
Rounding and unit differences. Sometimes it's not even a real conflict it's a unit mismatch (square feet vs. square yards) or simple rounding that makes numbers look inconsistent when they're actually close.
Incomplete or preliminary documents. Some bid sets are issued at 90% design completion, not 100%. Quantities can shift between issuance and final award, and if you don't know a set is preliminary, you might not expect the conflict at all.
Whatever the cause, the fix isn't to guess. It's to follow a process.
Step 1: Check the Order of Precedence Clause First
Most bid documents include a "precedence clause" or "order of precedence" section, usually buried in Division 00 or the general conditions. This clause tells you which document wins in a conflict typically addenda override specifications, specifications override drawings, and large-scale drawings override small-scale ones. Some contracts specify that written dimensions govern over scaled drawings, or that written quantities take priority over graphic representations.
Find that clause first. It often resolves the conflict on its own without any guesswork.
Step 2: Run Your Own Independent Quantity Takeoff
Never rely solely on quantities provided in the bid package — treat them as a reference point, not gospel. A careful, independent quantity takeoff from the actual drawings is the single best way to catch a conflict before it costs you money. If your own takeoff doesn't match either number in the documents, that's valuable information it tells you there may be a third, correct answer nobody has flagged yet.
This is exactly the kind of work a dedicated estimating team is built for. When you're juggling client calls, site visits, and subcontractor coordination, doing a meticulous, discrepancy-catching takeoff on every trade is hard to do consistently in-house. It's one of the main reasons contractors outsource estimation — not because they can't do takeoffs, but because a specialist team catches things a rushed internal review misses.
Step 3: Submit an RFI Don't Just Pick a Number and Hope
Once you've identified a real conflict, the correct move is almost always a Request for Information (RFI), submitted before the bid due date if at all possible. A good RFI does three things:
- States the specific conflict clearly (cite the drawing sheet number and the spec section).
- Explains why it matters to your bid (cost impact, schedule impact, or both).
- Asks a direct, answerable question rather than a vague one.
If the answer doesn't come back before bids are due, document your assumption in your bid submission itself. Never bid silently on a guess write it down. If you assumed 1,450 square feet of drywall because that's what the specification stated, say so in your qualifications or clarifications letter. This protects you if the conflict surfaces later during construction and someone tries to hold you to the lower number.
Step 4: When in Doubt, Bid the More Conservative Quantity
If time runs out and you can't get clarification, industry best practice generally favors bidding the higher of the two conflicting quantities, particularly for materials and labor-intensive scopes. It's a smaller risk to be slightly conservative and adjust during change order negotiations than to be short on material or labor hours mid-project with no contractual leg to stand on.
That said, this is a judgment call, and it should be paired with a clearly written assumption in your bid documents not silence.
Step 5: Flag the Discrepancy for an Addendum
If you're an estimator or contractor who catches a conflict early, it's worth notifying the design team or owner's representative, even if you're not required to. Getting an addendum issued that corrects the quantity benefits every bidder and creates a level playing field. It also builds your reputation as a thorough, trustworthy bidder something that matters more than people think when it comes to future work with the same GC or owner.
Prevention Beats Correction
The best way to handle conflicting quantities is to catch them before they ever affect your number. That means:
- Cross-referencing drawings, specs, and quantity schedules line by line
- Checking unit consistency across all documents
- Reviewing addenda carefully for quantity updates
- Running independent takeoffs rather than trusting provided numbers at face value
This is detailed, time-consuming work and it's exactly where a lot of bids quietly go wrong. Conflicting quantities that slip through unnoticed are one of the most preventable sources of margin loss in construction.
Final Thoughts
Conflicting quantities in bid documents aren't rare they're a normal part of construction bidding, and how you respond to them says a lot about the quality of your estimating process. Check the precedence clause, run your own independent takeoff, ask the right questions through a proper RFI, document your assumptions, and lean conservative when you have to guess.
If you'd rather not leave this to chance, that's exactly the kind of detail-level review our team handles every day. At Design Estimation, we provide professional construction estimation services designed to catch these discrepancies before they ever reach your bid so you're submitting numbers you can stand behind, not numbers you're hoping are right.
