Construction Project Cost Estimator
Accurate project cost estimation is essential for budgeting, comparing contractor bids, and securing financing. This calculator provides rough cost ranges for common residential construction and renovation projects based on national averages, adjusted for project scope and material grade.
Estimate Project Cost
Estimates based on national averages. Actual costs vary by location, contractor, site conditions, and material selections. Always obtain 3+ written bids from licensed contractors for accurate pricing. Permit costs vary by jurisdiction.
Average Project Costs by Type
| Project | Budget | Mid-Range | High-End | Unit |
|---|---|---|---|---|
| Kitchen Remodel | $75–$125 | $125–$250 | $250–$500+ | per sq ft |
| Bathroom Remodel | $100–$175 | $175–$350 | $350–$600+ | per sq ft |
| Room Addition | $80–$150 | $150–$300 | $300–$500+ | per sq ft |
| Basement Finish | $25–$50 | $50–$100 | $100–$200+ | per sq ft |
| Deck / Patio | $15–$30 | $30–$60 | $60–$120+ | per sq ft |
| Siding Replacement | $3–$6 | $6–$12 | $12–$25+ | per sq ft |
| Window Replacement | $300–$500 | $500–$800 | $800–$1,500+ | per window |
What Affects Project Cost
- Labor market — contractor availability and local wage rates are the single biggest cost variable. Urban areas and regions with construction booms command premium rates.
- Material grade — builder-grade cabinets vs. custom cabinetry can differ by 3–5x in cost for the same kitchen footprint.
- Scope creep — projects that uncover hidden issues (rot, mold, outdated wiring, asbestos) increase costs 15–30% on average. Budget a 10–20% contingency.
- Structural changes — moving walls, adding windows, or altering the roofline requires engineering, permits, and specialized labor.
- Permits and inspections — required for most work beyond cosmetic. Costs range from $200 for simple permits to $5,000+ for major additions. Unpermitted work can create legal liability and resale complications.
How to Compare Contractor Bids
When reviewing bids from licensed contractors, look beyond the bottom line:
- Scope of work — ensure each bid covers the same deliverables. Vague line items like “finish as needed” lead to disputes.
- Materials specified — bids should name specific products, not just “standard grade.” This prevents substitution of inferior materials.
- Timeline — completion date and penalty clauses for delays protect both parties.
- Payment schedule — never pay more than 10–15% upfront. Progress payments tied to milestones are standard practice.
- License and insurance — verify active license status and current general liability + workers’ compensation insurance before signing.
Frequently Asked Questions
How accurate are online cost estimators?
Online calculators provide rough order-of-magnitude estimates suitable for initial budgeting. Actual project costs depend on site-specific factors (access, existing conditions, local codes) that no calculator can fully account for. Treat estimates as a starting range, not a quote. Always get written bids from licensed contractors.
Should I budget for cost overruns?
Yes. Industry standard is to reserve 10–20% above the estimated cost as contingency. Renovation projects involving older structures should budget toward the higher end, as hidden conditions (outdated wiring, plumbing issues, structural concerns) are common and only discovered once work begins.
Do I need a general contractor or can I hire trades directly?
For projects involving multiple trades (electrical, plumbing, framing), a general contractor coordinates scheduling, manages permits, and ensures code compliance across all work. Hiring trades directly can save the GC markup (typically 10–20%) but requires the homeowner to manage coordination, scheduling, and inspection sequences — which most states require a licensed contractor to oversee for permitted work.