Not every construction estimate is built the same way. A developer testing whether a project is feasible needs a very different number than a general contractor submitting a lump-sum bid. Using the right type of estimate at the right stage saves time, sets realistic budgets and avoids unpleasant surprises later.
Below are the six most common types of construction estimates used on US projects, how they are prepared, and how accurate you can expect each one to be.
1. Conceptual (order-of-magnitude) estimate
A conceptual estimate is prepared at the very beginning of a project, often before any real drawings exist. It relies on historical cost data such as cost per square foot, cost per unit (per apartment, per hospital bed, per parking space) or cost data from similar completed projects.
- When to use it: feasibility studies, site selection, early financing conversations.
- Typical accuracy: broad. AACE International classifies early-stage estimates with expected ranges that can be as wide as -50% to +100%.
2. Preliminary (schematic) estimate
Once schematic design drawings are available, the estimator can break the project into major systems such as foundations, structure, envelope, interiors and MEP, and price each one using assemblies and parametric costs.
- When to use it: setting the owner’s budget and checking that the design is on track.
- Typical accuracy: tighter than a conceptual estimate, but still with meaningful contingency.
3. Design-development (detailed budget) estimate
As the design progresses, quantities can be measured for most systems and priced with current material and labor costs. This estimate is often used for value engineering, when the team looks for ways to reduce cost without reducing function.
- When to use it: design reviews, value engineering, lender and investor reporting.
4. Detailed (definitive) estimate
A detailed estimate is built from a complete quantity takeoff of construction documents. Every item is priced with material costs, labor hours, equipment, subcontractor quotes, general conditions, overhead and profit. This is the most accurate estimate type and the one contractors rely on for their final pricing.
- When to use it: final budgets, guaranteed maximum price (GMP) proposals, construction loans.
- Typical accuracy: the tightest range of all estimate types, because it is based on complete documents.
5. Bid estimate
A bid estimate is a detailed estimate prepared by a contractor to win a specific job. On top of the detailed cost, it reflects the contractor’s own crew productivity, subcontractor quotes, risk, schedule and desired margin. For subcontractors it is usually trade-specific, for example an electrical, drywall or concrete bid.
- When to use it: responding to invitations to bid, hard-bid public work and negotiated private work.
6. Control estimate and change order estimates
Once a contract is awarded, the winning estimate becomes the control budget used to track actual costs. During construction, change order estimates price added or deleted scope so the contractor is paid fairly for changes.
Quick comparison
| Estimate type | Project stage | Based on | Main purpose |
|---|---|---|---|
| Conceptual | Pre-design | Cost per sq ft / unit | Feasibility |
| Preliminary | Schematic design | Systems and assemblies | Owner budget |
| Design development | Design development | Partial quantities | Value engineering |
| Detailed | Construction documents | Full quantity takeoff | Final budget / GMP |
| Bid | Bidding | Detailed estimate + strategy | Win the contract |
| Control / change order | Construction | Contract estimate | Cost tracking |
How to choose the right estimate
Ask two questions: how complete are the drawings? and what decision does this number need to support? Early decisions only need conceptual numbers. Signing a contract or submitting a bid requires a detailed estimate built from a real takeoff.
Get the right estimate for your project
Buildup Estimation prepares conceptual, preliminary, detailed and bid estimates for residential, commercial and industrial projects in the US, Australia, the Caribbean and Europe, using location-based material and labor pricing. Learn more about our construction cost estimating services, browse sample estimates, or request a quote.
Frequently asked questions
Which type of construction estimate is most accurate?
A detailed (definitive) estimate based on a complete set of construction documents and a full quantity takeoff is the most accurate type of construction estimate.
What is the difference between a detailed estimate and a bid estimate?
A detailed estimate calculates the cost to build the project. A bid estimate starts from that cost and adds the contractor’s strategy, risk allowance, overhead and profit to set the price submitted to the owner.
Can you prepare an estimate before drawings are finished?
Yes. Conceptual and preliminary estimates are designed for early stages, using historical cost data and clearly stated assumptions.