How to Read a Construction Cost Estimate: A Guide for Developers and PE Firms

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A professional construction cost estimate breaks costs into hard costs (labor, materials, equipment), soft costs (design, permits, fees), and contingency. Estimates are also classified by accuracy level — AACE Class 1 through Class 5 — depending on how much design detail exists when the estimate is prepared. Knowing these categories is the fastest way to evaluate whether a budget is realistic.

A Cost Estimate Isn't Just a Number

For developers and PE firms evaluating a project, a cost estimate often arrives as a single bottom-line figure — the number everyone actually cares about. But that number is only meaningful in the context of what's behind it: what's included, what's excluded, and how much design certainty the estimate was built on.

Here's what to look for the next time you're handed a cost estimate and asked to approve a budget.

What's Included in a Professional Cost Estimate?

A well-built estimate is organized into clear categories rather than a single lump sum. At minimum, expect to see hard costs, soft costs, and contingency broken out separately, along with the assumptions behind each — the design basis, the pricing sources, and the date the estimate reflects.

Hard Costs vs. Soft Costs vs. Contingency: Where the Confusion Starts

Hard costs cover the physical construction — labor, materials, equipment, site work. Soft costs cover everything around the construction itself: design fees, permitting, testing, and other professional services. Contingency is the reserve set aside for the unknowns that haven't been resolved yet at the time the estimate is prepared.

Confusion — and disagreement — usually starts when these categories get blended together, or when contingency is presented as if it were a hard cost. Keeping the three separate is what makes an estimate possible to evaluate on its merits.

What Does 'Class' of Estimate Mean? (The AACE Classification System)

AACE International's classification system organizes estimates from Class 5 (earliest, lowest design detail — often a rough order of magnitude) to Class 1 (highest design detail, typically used for a final control estimate). The class of an estimate should tell you, at a glance, how much design work existed when the number was produced.

A Class 5 estimate and a Class 1 estimate can carry very different levels of accuracy for the same project — which is exactly why knowing the class matters before you treat either one as a fixed number.

Red Flags to Watch for in a Contractor's Estimate

Watch for unusually low contingency relative to the design stage, vague scope descriptions that leave room for later exclusions, and pricing that isn't tied to a clear design basis or date. An estimate that can't clearly explain its own assumptions is harder to defend later — to a lender, a board, or in a dispute.

Questions to Ask Your Estimator Before You Approve a Budget

Before signing off on a number, ask what class of estimate you're looking at, what design basis it was built from, how contingency was sized, and what's explicitly excluded. A good estimator should be able to answer all four clearly — and should welcome the questions rather than treat them as a challenge.

Frequently Asked Questions

Q: What is an AACE Class 3 estimate?

A: A mid-level, design-development estimate, typically prepared when the design is more developed than conceptual but not yet complete — used for budget authorization rather than final approval.

Q: What's a normal contingency percentage?

A: It varies by project phase and risk profile. Early-stage estimates typically carry higher contingency than estimates based on completed design; the right figure comes from benchmarking, not a flat rule of thumb.

Q: Why do two estimates for the same project differ so much?

A: Differences usually trace back to scope assumptions, escalation timing, or which soft costs were included — not the underlying math.

If you've been handed an estimate and aren't sure what's really behind the number, get a second opinion. Contact Carlos Estimating for an independent review before you approve your budget.