The 3 Most Costly Estimating Mistakes Contractors Make (And How to Avoid Them)

Estimating isn’t just about plugging numbers into a spreadsheet and hoping the job goes well. It’s the difference between a profitable season or a cash-crunch come winter. And let’s face it: for most contractors, estimating feels more like gut-feel than math.

Whether you’re building patios, maintaining lawns, or installing hardscapes, your estimate sets the tone for the entire job. But most contractors are unintentionally lowballing estimates and over-promising timelines because of a few avoidable mistakes. These small missteps in estimating lead to blown budgets, unpaid time, and ultimately, profit loss.

That’s why more landscapers are leaning on tools like landscape business management software to avoid common pitfalls. This guide will walk you through the 3 biggest estimating mistakes contractors make (yes, even the seasoned ones), why they happen, how much they’re costing you, and exactly how to fix them.

Mistake # 1: Estimating in Partial Day Chunks

The Problem:

Breaking jobs down into “half days” or “2.5 days” might feel precise, but it wrecks your profitability. You don’t just have to cover payroll for that half day—you still have to cover a full day’s worth of overhead (rent, insurance, equipment payments, landscaping crm software, etc.).

And once your crew leaves the job site at 1 PM, it’s too late to mobilize them on another project to earn the remaining revenue. The half day you estimated becomes a full day of expense without a full day of income.

Real World Example:

Say you estimate 165 man‑hours. You have a crew of 3 working 10 hours/day → 30 man‑hours/day. That’s 5.5 days of work.

If you bid 5.5 days, your client expects 5½ days.

But what happens during that “half day”?

• your crew might leave the job site at noon, but they’re not done for the day…technically. They’re probably heading back to the shop, cleaning tools, unloading materials, or prepping for the next job. You’re still paying them, so why aren’t those hours showing up in your estimates?
• In addition to that your overhead (rent, insurance, landscape estimating software, etc.) doesn’t shrink during that half day. The revenue earned during that half day won’t fully cover the overhead that was expected to be spread over a full day.

The Result:

Every time you estimate partial days, you eat the difference. Payroll, fuel, setup, and fixed costs chew up your margin, and you don’t even notice because your estimate only billed for “half” a day. Your margin disappears, and you didn’t even notice.

The Fix: 

Always estimate in full-day blocks. Round 5.5 days up to 6. Why? Because that last “half day” will still cost you a full day’s worth of overhead. By rounding up, you ensure every day of fixed costs is covered, and your profit margin stays intact.

|Pro Tip: Use landscape scheduling software to simplify scheduling. When every estimate is built in full-day increments, your calendar is easier to manage and you stop running into “dead afternoons” that cost you money.