A good estimate can win you a job. A bad one can cost you time, money, and credibility. Whether you’re new to estimating or have been doing it for years, it’s easy to fall into habits that quietly hurt your bottom line.
Here are the top 5 mistakes I see subcontractors make when estimating and how to avoid them.
We’ve all been there. You get a last-minute bid invite and feel the pressure to turn something in before the deadline. But skimming through the plans without fully understanding the scope is one of the quickest ways to miss key details or worse, bid on something you’re not responsible for.
What to do instead:
Take the time to review the drawings thoroughly, especially the notes, specs, and scope clarifications. If you’re unsure about something, don’t guess. Send an RFI or ask the GC for clarification.
Some trades overlap in scope, especially on larger or more complex jobs. For example, who’s providing blocking? Who’s supplying fixtures or sealants? If you don’t catch those gray areas, you may underbid and end up covering work you didn’t plan on.
What to do instead:
Create a checklist of scope items specific to your trade. Cross-reference the architectural, structural, and MEP plans. Make sure your bid notes clearly state inclusions and exclusions.
Material prices fluctuate. Labor productivity varies from crew to crew. Relying on gut instinct or “ballpark” numbers can throw your estimates off by thousands of dollars.
What to do instead:
Use a reliable database like Craftsman or RSMeans for updated unit costs or track your own job data to build historical pricing. Factor in project-specific conditions that affect labor efficiency like site access, height, or weather.
Too many subcontractors aim low to stay competitive but forget to account for overhead, profit, or contingency. That might win you the job but it could also mean working at cost or even a loss.
What to do instead:
Build in a consistent markup that reflects your business needs, not just what you think the GC wants to see. Don’t undervalue your work. A solid estimate protects your margins and keeps your company sustainable.
Even experienced estimators make data entry errors, forget to attach documents, or leave out items. One small mistake can throw off your entire bid.
What to do instead:
Always do a final review. Check your quantities, formatting, attachments, and scope notes. If possible, have a second set of eyes look it over. This step only takes a few minutes and can prevent costly issues down the line.
Estimating is part math, part strategy, and part communication. Avoiding these common mistakes can help you submit more confident, competitive bids and win more of the right work.
If estimating is taking too much of your time or you’re unsure about your current process, consider getting some support. At Priority Estimating Services, we help subcontractors produce accurate, clear, and professional estimates without the stress.
📩 Contact us to learn how we can help lighten your load and sharpen your bids.
