Use BuildMath to estimate early construction cost, renovation budget, floor area, cap rate, net operating income, and office-to-residential feasibility directly in your browser.
These calculators are designed for early planning and rough order-of-magnitude analysis. They help users compare assumptions before deeper professional review.
Estimate preliminary project cost using gross floor area, hard cost per square foot, soft costs, and contingency.
Estimated Hard Cost
$0Estimated Soft Cost
$0Estimated Contingency
$0Estimated Total Project Cost
$0Hard Cost = Gross Floor Area × Hard Cost per Square Foot
Soft Cost = Hard Cost × Soft Cost Percentage
Contingency = Hard Cost × Contingency Percentage
Total Project Cost = Hard Cost + Soft Cost + Contingency
Estimate renovation budget using renovation area, scope level, soft costs, and contingency.
Estimated Hard Cost
$0Estimated Soft Cost
$0Estimated Contingency
$0Estimated Renovation Budget
$0Hard Cost = Renovation Area × Cost per Square Foot
Soft Cost = Hard Cost × Soft Cost Percentage
Contingency = Hard Cost × Contingency Percentage
Total Renovation Budget = Hard Cost + Soft Cost + Contingency
Calculate room area, total room area, support area, and estimated total floor area.
Area per Room
0 SFTotal Room Area
0 SFEstimated Support Area
0 SFEstimated Total Floor Area
0 SFArea per Room = Room Length × Room Width
Total Room Area = Area per Room × Number of Similar Rooms
Support Area = Total Room Area × Support Area Percentage
Total Floor Area = Total Room Area + Support Area
Estimate property return from annual net operating income and property value.
Net Operating Income
$0Property Value
$0Estimated Cap Rate
0.00%Cap Rate = Net Operating Income ÷ Property Value × 100
A higher cap rate may indicate higher income yield, but it can also reflect higher risk or weaker asset quality.
Calculate annual property income after vacancy loss and operating expenses.
Effective Gross Income
$0Total Operating Expenses
$0Net Operating Income
$0Effective Gross Income = Gross Annual Rental Income + Other Income - Vacancy Loss
Net Operating Income = Effective Gross Income - Operating Expenses
Estimate residential area, unit count, conversion cost, rent potential, and rough office-to-residential feasibility.
Estimated Net Residential Area
0 SFEstimated Unit Count
0Estimated Conversion Cost
$0Gross Annual Rent Potential
$0Effective Annual Rent After Vacancy
$0Rough Rent-to-Cost Ratio
0.00%Net Residential Area = Existing Office Floor Area × Residential Efficiency
Estimated Unit Count = Net Residential Area ÷ Average Unit Size
Estimated Conversion Cost = Existing Office Floor Area × Conversion Cost per Square Foot
Effective Annual Rent = Unit Count × Monthly Rent × 12 × (1 - Vacancy Percentage)
Last updated: May 2026
Use the calculators to create fast order-of-magnitude estimates before hiring consultants, requesting bids, or committing to a project direction.
Evaluate property income, cap rate, conversion potential, and early feasibility assumptions in one browser-based tool set.
The calculators are free to use and run directly in the browser. Results depend on the assumptions entered by the user.
Early construction cost estimating usually starts with three core assumptions: project size, hard cost per square foot, and additional percentages for soft costs and contingency.
Cap rate compares annual net operating income to property value. It is commonly used as a quick income-return indicator for real estate assets.
Office-to-residential conversion depends on more than floor area. Early testing should consider usable residential efficiency, unit depth, façade access, core location, systems, and code requirements.
BuildMath is a free collection of browser-based calculators for early real estate and construction planning.
The tools help owners, developers, architects, brokers, investors, and project teams create quick preliminary estimates for construction cost, renovation budget, floor area, cap rate, net operating income, and office-to-residential conversion feasibility.
BuildMath is designed for early-stage planning only. It helps users compare assumptions, understand rough order-of-magnitude outcomes, and identify when deeper professional review is needed.
BuildMath provides browser-based calculators for real estate and construction planning. Calculator inputs are processed in the browser to generate on-screen estimates.
BuildMath does not require users to create an account or submit personal information to use the calculators.
If users contact BuildMath by email, the information provided may be used only to respond to the inquiry.
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For questions, feedback, or calculator suggestions, contact BuildMath at:
contact@logica.design
BuildMath is operated as part of the Logica design and planning ecosystem.