Condominium Building Development Back of the Envelope Calculator

Condominium Building Development Analysis Back of the Envelope Calculator

A back of the envelope, or “BOTE” analysis, is intended to give you a broad brushstroke view of the economic feasibility of a potential transaction. BOTE-level analysis is used to quickly screen potential deals in and out of one’s deal pipeline. A high level of detail is purposefully forfeited in BOTEs for the sake of speed of execution.

For a residential condominium building development, BOTE feasibility analysis focuses in on the Land Purchase Price as it relates to the project’s development profit margin. Land Purchase Price is typically solved for on a residual basis, meaning the land value is what is left over after a targeted pre-income tax profit has been achieved.

The development back of the envelope thought experiment

Development BOTE analysis for condominiums assumes the hypothetical situation where you could purchase the land at an assumed price today and then snap your fingers and the contemplated building would instantly appear and be sold out. As such, today’s hard and soft development costs, cost of debt and sales prices are used as inputs. The logic behind doing this is that if the deal does not look good using today’s values, about which we have a very high level of certainty, it’s not worth pursuing because we have significantly less certainty about the amounts to use for these variables years into the future.

Click on any blue input value to make changes. Hit Enter or Tab after you have made an input, and then click on the next input field to edit it. Click the Save file button at the top to save your work periodically. A tutorial video is at the very bottom of the page.

FAR-Based vs. Units-Based analysis

A development site zoned for multi-unit residential use will typically have a density constraint in terms of the total gross square footage of building allowed on the site or a ceiling on the residential unit count. Our calculator has the ability to analyze a site both on an FAR basis as well as on a Units basis, and you can toggle between the two within a single analysis file. FAR stands for floor area ratio, but we like to think of it as “floor area to lot size ratio.” FAR is simply the ratio of the allowable above-ground gross building area to the site area. An example of an FAR ratio of 5.00 would be a 10,000 square foot development parcel with an allowable above-ground building area of 50,000 gross square feet.

Understanding the Sensitivity Analysis tables

Sensitivity analysis is a way of stress-testing key calculation-based outputs based on the changing of one or more inputs that impact the output in question. Each of our calculator’s Profit Margin sensitivity analyses shows the intersection of two key inputs, with increments of change for each input, and the resulting spectrum of values for the profit margin.

If you have been following REFM, you may remember that this tool used to be offered in Excel. Recognizing that these BOTEs are often run in the field, and that Excel is just plain awful to use on your phone, we put all of the capabilities of the Excel template onto Valuate® so you can run analyses comfortably no matter where you are. Enjoy.

View the calculator on your phone here

How to do a back of the envelope analysis for developing a condominium building

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