Commercial Lease Space Build-Out Cost Calculator
Estimate the total cost to build out a commercial lease space, your net out-of-pocket expense after tenant improvement (TI) allowances, and how that cost can be amortized over your lease term.
Formulas Used
Gross Build-Out Cost = Square Footage × Cost per Sq Ft
Contingency Amount = Gross Build-Out Cost × (Contingency % ÷ 100)
Total Build-Out Cost = Gross Build-Out Cost + Contingency Amount
Total TI Allowance = TI Allowance per Sq Ft × Square Footage
Net Tenant Cost = max(0, Total Build-Out Cost − Total TI Allowance)
Effective Net Cost per Sq Ft = Net Tenant Cost ÷ Square Footage
Monthly Amortized Cost = Net Tenant Cost ÷ (Lease Years × 12) [straight-line, no interest]
Assumptions & References
- Build-out cost benchmarks are U.S. national averages (2023–2024) sourced from CBRE, JLL, and BOMA research: Basic/Shell ~$40–$70/sq ft; Standard Office ~$70–$100/sq ft; Mid-Range Retail/Medical ~$100–$160/sq ft; High-End/Specialty ~$150–$250+/sq ft.
- A 10% contingency is the industry-standard buffer recommended by the Construction Management Association of America (CMAA) for tenant improvement projects.
- Tenant Improvement (TI) Allowance is a landlord concession paid per square foot toward the tenant's build-out; typical ranges are $20–$80/sq ft depending on market and lease term length.
- Amortization shown is straight-line (no financing cost). If you finance the net cost, add your lender's interest rate to determine true monthly carrying cost.
- Costs do not include furniture, fixtures & equipment (FF&E), moving expenses, IT/AV infrastructure, or soft costs such as architect/permit fees unless embedded in your custom per-sq-ft figure.
- Permit and architectural fees typically add 5–15% to hard construction costs (AIA, 2023).
- Results are estimates only. Obtain contractor bids and consult a commercial real estate attorney before signing a lease.