- The Seven Cost Buckets
- Hard vs Soft Costs: The Practical Split
Construction estimating is forecasting the total cost of a project before any dirt is moved. The number a contractor signs has to cover materials, labor, equipment, subcontractors, overhead, profit, and an honest contingency. Get any one of those wrong and the project margin lands at zero. This guide walks through the basics with real numbers from current industry sources.
Quick Answer Construction estimating breaks total cost into seven buckets: materials, labor, equipment, subcontractors, hard cost contingency, soft costs (permits, insurance, design), and overhead plus profit. The five AACE estimate classes range from Class 5 (rough order of magnitude, accuracy -50% to +100%) to Class 1 (definitive, accuracy -5% to +15%). For 2026, the construction industry average net profit margin is 5 to 6 percent, and a healthy general contractor targets 8 to 10 percent. Overhead typically runs 8 to 15 percent of revenue.
Key Takeaways
- The five AACE International estimate classes range from Class 5 (-50% to +100% accuracy) to Class 1 (-5% to +15% accuracy), based on how mature the project definition is.
- Construction industry average net profit margin sits at 5 to 6 percent in 2025, with well-managed GCs targeting 8 to 10 percent, per Bridgit's profit margin benchmarks.
- Overhead and profit (OH&P) markup typically lands at 15 to 25 percent of direct costs, per Buildern's general contractor markup guide.
- Building material prices were up 3.5 percent year over year in September 2025, the largest jump since early 2023, per the BLS Producer Price Index summarized by NAHB.
- Change orders cost an average of 10 percent of contract value, per Rhumbix's change order analysis.
- Standard documents matter. AIA G701 is the change order form, G702 is the application for payment, G703 is the continuation sheet.
This guide is built for small to mid-size general contractors, subs, and remodelers who quote work between $25,000 and $5 million. The fundamentals do not change at larger scale; the documentation does.
The Seven Cost Buckets
Every construction estimate, no matter how small, breaks into the same seven buckets. The accuracy of the total depends on getting each one separately right.
1. Materials
Materials are the physical inputs: lumber, concrete, drywall, fixtures, finishes. Material costs are estimated through a quantity takeoff, where you measure the drawings to count units and apply unit prices.
A useful rule of thumb on materials in 2026: prices are still climbing modestly. The NAHB analysis of BLS data showed building material prices up 3.5 percent year over year in September 2025, the largest annual increase since early 2023. Metal products are leading the way, up nearly 50 percent in some categories. Softwood lumber is below last year's levels, and ready-mix concrete is softening.
Practical takeaway: pull current pricing from suppliers within the last 30 days for any material that swings (metals, asphalt, fuel-tied items). Use historical pricing only for stable items (drywall, fasteners, basic fixtures).
2. Labor
Labor is the cost of crew time. Estimate by:
- Listing each scope (framing, drywall, paint, etc.)
- Estimating crew hours per scope
- Multiplying by the burdened labor rate (wages + payroll taxes + workers comp + benefits)
The burdened rate is typically 1.3x to 1.5x the raw hourly wage. A $35 per hour carpenter costs the contractor roughly $48 to $52 per hour all in.
Per the BLS data, service prices have risen 3.0 percent year over year as of 2025, slightly outpacing material price growth.
3. Equipment
Equipment is either owned (depreciation + maintenance + operator time) or rented (rental rate + fuel + operator time). For small jobs, equipment is a small line item. For excavation, lift work, or heavy demolition, it can be 5 to 15 percent of the total.
4. Subcontractors
Subcontractor costs are quoted to you by the sub. The discipline is in soliciting at least three bids for any scope above a few thousand dollars, comparing apples to apples, and writing the scope down clearly enough that the sub cannot increase the price later under "what you described was not what was on the drawing."
5. Hard Cost Contingency
A line item that covers known unknowns within the build (a wall that turns out to be load-bearing, soil that needs more remediation than the geotech report suggested, fixtures that go out of stock). Typically 3 to 10 percent of hard costs depending on project complexity and how mature the design is.
The contingency is not profit. It belongs to the project. If unused, it returns to the owner (or to your margin if you bid fixed price).
6. Soft Costs
Soft costs are everything that is not the physical build. Permits, design fees, insurance, financing, surveys, environmental reports, project management. On a typical small commercial project, soft costs run 10 to 20 percent of hard costs. On a residential remodel, they are usually a smaller share.
7. Overhead and Profit (OH&P)
Overhead is the cost of running your business that is not tied to a single project: rent, office staff, insurance, vehicles, software. Profit is what is left over after everything else is paid.
Per Buildern's 2026 industry data, OH&P markup typically lands between 15 percent and 25 percent of direct costs. Smaller contractors with leaner overhead can run lower; larger firms with more administrative load run higher.
Hard vs Soft Costs: The Practical Split
The distinction matters because lenders, owners, and tax accountants all care about it.
| Hard costs | Soft costs |
|---|---|
| Materials | Architectural and engineering fees |
| Labor | Permits and impact fees |
| Equipment | Insurance (builder's risk, GL) |
| Subcontractors | Financing and interest |
| Hard cost contingency | Marketing, sales, broker fees |
| Project management and supervision | |
| Surveys, environmental reports | |
| Soft cost contingency |
Hard costs are roughly 70 to 80 percent of total project cost on a typical commercial project. Soft costs are 20 to 30 percent. Residential remodels skew higher on hard costs (less permit and design work) and lower on soft costs.
The Five AACE Estimate Classes
Construction (and process engineering) uses a five-class estimating framework defined by AACE International's Recommended Practice 18R-97. The class depends on how mature the project definition is, which determines how accurate the estimate can be.
| Class | Project definition | Typical accuracy | Use case |
|---|---|---|---|
| Class 5 | 0 to 2 percent (concept) | -50% to +100% | Feasibility, screening |
| Class 4 | 1 to 15 percent (early schematic) | -30% to +50% | Budget authorization |
| Class 3 | 10 to 40 percent (schematic done) | -20% to +30% | Funding decision |
| Class 2 | 30 to 75 percent (design developed) | -15% to +20% | Control budget |
| Class 1 | 65 to 100 percent (construction documents) | -5% to +15% | Bidding, final estimate |
The single most common estimating mistake at small contractor scale is quoting a Class 1 price (a fixed bid) on a Class 3 set of drawings. The math is impossible. If the drawings are incomplete, the estimate has built-in error that exceeds your profit margin. Either insist on more complete drawings, or quote as a "budget" with appropriate uncertainty.
Quantity Takeoff: The Foundation of a Real Estimate
Quantity takeoff is the line by line measurement of what the drawings show. Done right, it produces a defensible itemized list. Done wrong, you have a guess with units attached.
The typical takeoff process:
- Pull dimensions from the drawings. Length, area, volume, count.
- Group by trade or scope. All framing materials together, all drywall together.
- Apply waste factors. Lumber is typically 10 percent. Drywall is 10 to 15 percent. Concrete is 5 to 10 percent depending on form complexity.
- Apply unit prices from current supplier quotes. Within 30 days for volatile materials.
- Roll up to a line item per scope.
Modern takeoff is mostly done in software (PlanSwift, Bluebeam Revu, Autodesk Construction Cloud, On-Screen Takeoff). The math is unchanged from paper takeoffs; the speed is roughly 5x faster.
Labor Estimating: Crew Hours and Production Rates
Labor is the bucket where most small contractors miss. The fix is to estimate production rates: how many units a crew can install per day.
Example production rates (the rate that a typical crew completes the scope in one productive day):
| Scope | Crew | Production rate per day |
|---|---|---|
| 2x4 framing (linear feet, partition walls) | 2 carpenters | 200 to 300 lf |
| 1/2" drywall hang | 2 hangers | 50 to 80 sheets (1600 to 2560 sf) |
| Drywall finish (level 4) | 2 finishers | 1500 to 2500 sf |
| Interior paint (2 coats) | 2 painters | 1500 to 2200 sf |
| Asphalt paving | 4-person crew | 5,000 to 8,000 sf |
| Roof shingles (architectural) | 3-person crew | 30 to 40 squares |
Note: these are illustrative. Your actual rates depend on crew skill, site conditions, and project complexity. The discipline is to track your own rates against estimates after every project and build your own table.
To estimate labor cost for a scope:
Labor cost = (Total units / production rate per day) x crew daily cost
Example: 1,200 lf of framing, crew of 2 at 250 lf/day, $1,200/day burdened crew cost:
Labor cost = (1,200 / 250) x $1,200 = 4.8 x $1,200 = $5,760
This is the right way to estimate, because the production rate is what you can verify against actuals.
A Worked OH&P Calculation
Per Bridgit's profit margin data, the construction industry average net profit margin sits at 5 to 6 percent in 2025. The benchmark for well-managed companies is 5 to 8 percent. Healthy GCs target 8 to 10 percent net margins.
To get there, the markup on direct costs has to cover overhead first, then add profit.
Example: a small GC with annual overhead of $400,000 and projected revenue of $4,000,000.
Overhead as percent of revenue = $400,000 / $4,000,000 = 10 percent
That 10 percent comes off the gross margin first. If the target net profit is 8 percent, then the total markup on direct costs needs to be roughly:
Markup = Overhead percent + Profit percent
= 10 percent + 8 percent (net) / (1 - 10 percent - 8 percent)
≈ about 22 percent of direct costs
This lines up with the Buildern markup range of 15 to 25 percent for typical OH&P.
The lesson: if you charge a flat 10 percent markup, you do not have a profit margin. You have an overhead recovery rate.
The AIA Document Map
For projects on AIA contracts, three forms recur on almost every job. Knowing what each does saves time and prevents disputes.
| Form | Name | Purpose |
|---|---|---|
| AIA G701 | Change Order | Documents agreed scope changes, cost adjustments, and time impact. Signed by owner, architect, and contractor. |
| AIA G702 | Application and Certificate for Payment | The contractor's request for payment for work completed to date. Architect certifies and forwards to owner. |
| AIA G703 | Continuation Sheet | The line-item breakdown that supports the G702 totals. |
Per Procore's AIA G701 guide, the G701 explicitly states "NOT VALID UNTIL SIGNED BY THE ARCHITECT, CONTRACTOR AND OWNER." All three signatures matter. A change order signed only by the project manager and the contractor is not enforceable under most AIA contracts.
For estimate-to-invoice flow on non-AIA contracts, see our estimate vs invoice best practices guide for the simpler version of the same workflow.
A Practical Estimating Workflow
A defensible estimating workflow for a small GC looks like this:
1. Review the Bid Package
Drawings, specs, addenda, site plan, geotech report if available. Spot the holes. Mark every place where the drawings are ambiguous or missing detail. Those become assumptions or RFIs.
2. Site Visit
If the project is on existing conditions, walk the site. Photos and notes. Existing conditions are the single biggest source of overruns. Things you cannot see from the drawings: hidden plumbing routes, structural surprises, access constraints.
3. Quantity Takeoff
Trade by trade. Apply waste factors. Cross-check the totals against the floor plan square footage to make sure nothing is missed.
4. Solicit Pricing
For materials, current supplier quotes. For subcontractors, three bids minimum on anything above a few thousand dollars. Use a clear scope letter to the subs so the bids are comparable.
5. Apply Labor Rates
Burdened labor rates times production-rate-derived hours. Use your own production rates if you have them, industry rates (RSMeans, Procore) if you do not.
6. Add Equipment, Soft Costs, and Contingency
Equipment by line. Soft costs as a list (permits, insurance, design). Contingency as a percentage of hard costs, scaled by project complexity.
7. Apply Overhead and Profit
OH&P as a markup on direct costs. The number depends on your specific overhead burden. Most small GCs land at 15 to 22 percent.
8. Cross-Check and Submit
Compare the total against a comparable past project (reference class). Compare per-square-foot cost against industry benchmarks. If anything looks off by more than 15 percent, find out why before submitting.
For deeper reference class techniques, see our guide to estimating project hours accurately, which covers the same idea applied to time instead of cost.
Common Estimating Pitfalls
The patterns we see most often in small contractor estimates:
- No site visit on existing-conditions work. The drawings never tell the whole story.
- Old unit prices. Material prices moved 3 to 5 percent in 2025. Stale prices means stale estimates.
- Missing waste factors. A pristine takeoff with no waste is an underestimate.
- No subcontractor scope letters. Sub bids without a written scope produce arguments at change order time.
- Single contingency line covering everything. Soft cost contingency and hard cost contingency are different risks.
- OH&P calculated as a markup without checking against overhead. A 10 percent markup on a 12 percent overhead company is losing money on every job.
- Quoting Class 1 prices on Class 3 documents. The math does not work.
Estimating Software vs Spreadsheets
For small remodel and trade work, a well-built spreadsheet works. For commercial GC work above $500,000, dedicated estimating software pays for itself within the first project.
| Tool category | When to use |
|---|---|
| Excel or Google Sheets | Sub-$100k residential remodels, single-trade work |
| Dedicated estimating software (PlanSwift, Bluebeam Revu, STACK) | Above $100k, multi-trade, drawings in PDF or CAD |
| Integrated platforms (Procore, Autodesk Construction Cloud) | Above $1M, multi-project portfolio, design coordination |
| Specialty databases (RSMeans, Procore cost data) | Cost data inputs for any tool |
The software does the takeoff math faster. It does not produce a better estimate than the estimator using it. Garbage in, faster garbage out.
How Change Orders Affect Original Estimates
Per Rhumbix's change order analysis, change orders average 10 percent of contract value, with some projects experiencing up to 25 percent. The AIA's "Truth About Change Orders" paper puts the industry standard at 8 to 14 percent.
The implication for estimating: a fixed-price estimate is not a fixed-price project. Change orders are normal. The estimate's job is to be defensible at signing. The change order's job is to handle everything that comes after.
Pre-define in the contract:
- The change order process (written, signed, before work)
- The markup on change order work (typically 15 to 25 percent on top of cost)
- The time impact rules (extension days for added scope)
For the change order playbook in detail, see our guide on how to handle estimate revisions.
FAQ
How do I estimate in construction step by step? The eight steps are: review the bid package, visit the site, perform the quantity takeoff, solicit material and subcontractor pricing, apply burdened labor rates, add equipment and soft costs, add hard cost contingency, then apply overhead and profit markup. Cross-check the total against a comparable past project.
What are the four types of estimating? Outside the formal AACE five-class system, the four practical types are: rough order of magnitude (concept stage), preliminary (early design), detailed (full design), and definitive (construction documents). These map roughly to AACE Class 5, Class 4, Class 3, and Class 1.
What is the 0.6 rule for cost estimating? The 0.6 rule, also called the six-tenths rule, is a scaling shortcut used in process engineering to estimate the cost of a larger or smaller version of a known piece of equipment. The cost of capacity B equals the cost of capacity A times (B/A) raised to the 0.6 power. It is not commonly used for building construction; it applies to industrial process equipment.
Can ChatGPT do construction estimates? ChatGPT can help with a rough estimate from a description, draft scope letters to subs, and explain estimating concepts. It cannot do an accurate quantity takeoff from drawings, and it cannot price current material costs without being given current data. Treat AI as an assistant for first drafts and explanations, not as the estimator.
What percentage should I add for contingency? Hard cost contingency is typically 3 to 10 percent on well-defined projects, higher on projects with existing-conditions risk. Soft cost contingency is typically 5 to 15 percent. The two are separate because they cover different risks.
What is OH&P and how much should I charge? OH&P is overhead plus profit. Overhead is the cost of running your business; profit is what you take home. Typical OH&P markup is 15 to 25 percent of direct costs, per Buildern's industry data. The right number for you depends on your specific overhead burden as a percent of revenue.
How accurate should my estimate be? The AACE class tells you. A Class 5 conceptual estimate has accuracy of -50% to +100%. A Class 1 definitive estimate has accuracy of -5% to +15%. Your estimate cannot be more accurate than the maturity of the drawings allows.
Do I need to use AIA contract forms? No, but if you do not, you need an equivalent. AIA G701, G702, and G703 are the industry standard for change orders, payment applications, and continuation sheets. ConsensusDocs and EJCDC are alternatives. Custom contracts work too, but the burden is on you to make sure they cover the same ground.
When This Guide Isn't for You
- Residential remodels under $25,000. The full quantity takeoff and AACE class framework is overkill. A clean line-item estimate with materials, labor, and a 10 to 15 percent contingency is enough.
- Engineered procurement on industrial projects. Process engineering uses different scaling rules (the 0.6 rule mentioned above, ENR cost indices). The frameworks here apply but the unit cost data is different.
- Public works bidding. Federal and state public works projects have specific labor categories (Davis-Bacon wages), bonding requirements, and reporting that go beyond this guide. The US SBA federal contracting resources cover that area.
- Time-and-materials work. If you are billing T&M, you do not need a fixed estimate. You need a clear hourly rate, a markup on materials, and a regular billing cadence.
How We Verified This
- AACE estimate class accuracy ranges come from AACE International Recommended Practice 18R-97.
- Industry profit margin data (5 to 6 percent average, 8 to 10 percent for healthy GCs) comes from Bridgit's construction profit margin analysis and Aladdin Bookkeeping's 2025 benchmarks.
- OH&P markup ranges (15 to 25 percent) come from Buildern's general contractor markup guide.
- 2025 material price changes come from the Bureau of Labor Statistics Producer Price Index as summarized by NAHB Eye On Housing.
- Change order data comes from Rhumbix's change order analysis and the AIA's "Truth About Change Orders" paper.
- AIA document descriptions (G701, G702, G703) come from Procore's AIA G701 guide and the official AIA Contract Documents site.
- Production rate ranges are typical values from industry references like Procore's construction estimating library. Your actual rates may differ; the guide notes this.
Where sources disagreed (most commonly on average margin), we used the broader industry benchmark and noted the range.