Contractor Business Guide
12 Common Contractor Bidding Mistakes
Every contractor has lost money on bad bids. But most bidding mistakes are predictable and preventable. Here are the most common errors and how to fix them before they cost you thousands.
Quick Answer
The biggest bidding mistakes: underestimating labor hours, forgetting overhead, confusing markup with margin, and bidding on every lead. Fix these four and you’ll eliminate 80% of bid-related profit losses.
Mistake #1: Underestimating Labor Hours
This is the #1 profit killer. Contractors consistently underestimate how long work actually takes. Optimism bias, forgetting setup/cleanup time, and not accounting for complications lead to labor overruns on nearly every job.
The Fix
Track actual hours vs estimated on every job. After 10-20 jobs, you’ll know your real production rates. Multiply your “gut feel” estimate by 1.25-1.5 until you have data. Always add time for setup, cleanup, and the unexpected.
Mistake #2: Forgetting Overhead
Pricing as “materials + labor + a little profit” ignores the 25-45% overhead cost of being in business. Insurance, vehicles, tools, office costs, and administrative time must be recovered from jobs. If you don’t include overhead, you’re paying it out of pocket.
The Fix
Calculate your actual overhead percentage annually. Add this to every bid before profit. Formula: Bid = Direct Costs × (1 + Overhead%) ÷ (1 – Profit%). See our Overhead & Profit Guide.
Mistake #3: Confusing Markup with Margin
A 20% markup does NOT give you 20% profit. It gives you 16.7% margin. This confusion costs contractors thousands per job. To achieve 20% profit margin, you need 25% markup.
The Fix
Use the margin formula: Markup = Target Margin ÷ (1 – Target Margin). For 20% margin, you need 20% ÷ 80% = 25% markup. Use our Markup Calculator.
Mistake #4: Bidding on Every Lead
Every bid costs time and money (2-8 hours per detailed estimate). Bidding on jobs you won’t win or don’t want wastes resources that could go toward better opportunities. Low win rates indicate poor lead qualification.
The Fix
Qualify leads before bidding. Ask about budget, timeline, decision process, and competition. If the answers don’t fit, politely decline. Target 25-35% win rate. Below 15% means you’re wasting time; above 50% means you’re too cheap.
Mistake #5: Forgetting Small Items
Fasteners, caulk, tape, blades, fuel, dump fees, and consumables add up fast. These “small” items can represent 5-15% of job cost. Forgetting them means they come out of profit.
The Fix
Create a checklist of commonly forgotten items for your trade. Add a line item for “miscellaneous materials” at 5-10% of materials cost, or itemize every consumable.
Mistake #6: Using Incorrect Labor Rates
Using base wage ($25/hour) instead of fully burdened rate ($35-45/hour) underprices every job. Workers comp, payroll taxes, benefits, and training add 35-50% to base wages.
The Fix
Calculate your true burdened labor rate: Base wage + payroll taxes (7.65%) + workers comp (8-25% depending on trade) + benefits + training. Use this rate in all estimates.
Mistake #7: No Contingency for Unknowns
Remodels and repairs always have surprises. Rot, mold, non-code work, and hidden conditions turn profitable jobs into losers if you haven’t budgeted for them.
The Fix
Add contingency to every bid: 5-10% for new construction, 10-15% for typical remodels, 15-25% for older homes. If unused, it becomes profit. If needed, it saves the job.
Mistake #8: Vague Scope of Work
“Remodel bathroom” means different things to different people. Vague scopes lead to disputes, scope creep, and unpaid work. Customers assume everything is included; contractors assume nothing extra is.
The Fix
Write detailed scope that specifies what IS included and what is NOT. Include quantities, materials, brands, and specs. The more detail, the fewer disputes.
Mistake #9: No Change Order Process
“While you’re here, can you also…” is the scope creep that kills profits. Without a change order process, extra work goes unbilled or causes disputes at final payment.
The Fix
Any work beyond original scope requires a written change order with price, signed before work begins. Train customers to expect this from the first meeting. No signature, no extra work.
Mistake #10: Racing to the Bottom on Price
Cutting price to win jobs creates a race to the bottom. You attract price-shoppers, make less money, and still have to deliver quality. Low-price wins lead to corner-cutting and callbacks.
The Fix
Compete on value, not price. Differentiate through professionalism, detailed estimates, warranties, and communication. If a customer only cares about price, they’re not your customer.
Mistake #11: No Follow-Up System
80% of sales happen after the 5th follow-up, but most contractors give up after one. Sending a bid and waiting for a call loses winnable jobs to more persistent competitors.
The Fix
Create a follow-up system: Day 1 (send bid), Day 3 (check-in call), Day 7 (email), Day 14 (final call). Use a CRM to track. Persistence wins jobs.
Mistake #12: Not Learning from Lost Bids
Every lost bid is data, but most contractors never ask why they lost. Without feedback, you repeat the same mistakes and miss opportunities to improve.
The Fix
When you lose a bid, call and ask why. Was it price, timing, trust, scope? Track reasons over time to identify patterns. Adjust your approach based on data, not guesses.
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