Step 1: Know Your Sale Number
Start with the number you can get today: what a developer would pay for your site as-is, based on its buildable square footage and current land comps. This is a known, immediate figure — no construction risk, no multi-year timeline, no market uncertainty between now and a future closing. See our land valuation guide for exactly how this number gets built.
Step 2: Know Your Development Number — All In
Next, build the honest self-development number. This means the finished project's value (based on projected sale or stabilized rental income) minus every cost of getting there: hard costs, soft costs, construction financing, and the opportunity cost of your equity being tied up for the 2–4 years most NYC ground-up projects take from start to stabilized income. Our development cost breakdown walks through each of these categories in detail.
Step 3: Adjust for Risk and Time
This is the step most back-of-envelope comparisons skip. A dollar in hand today is not equivalent to a dollar you might receive in three years, after assuming construction cost risk, financing rate risk, and market risk on what the finished building will actually be worth when it's done. A rigorous comparison discounts the future development number to reflect that risk and delay — not just for the time value of money, but for the real possibility that costs run over or the market softens before you're finished.
The right comparison isn't "sale price vs. finished building value." It's "sale price today" vs. "risk-adjusted, time-adjusted net proceeds from a project that hasn't been built yet." Those are very different numbers, and the gap between them is often smaller than owners initially assume.
Step 4: Weigh What You Can't Put a Number On
Some factors don't fit neatly into the spreadsheet but matter just as much: whether you have the bandwidth and appetite to manage a multi-year construction project, whether you're personally guaranteeing construction debt, and what else that capital and attention could be doing if it weren't tied up in a single development. Our sell vs. build it yourself guide covers this side of the decision in more depth.
Where the Break-Even Point Usually Falls
In practice, self-development tends to make the most sense when the spread between land value and all-in development cost (adjusted for risk and time) is wide, and when the owner has real development experience and risk tolerance. When that spread is thin — which is common in today's higher construction-cost, higher-interest-rate environment — a known sale price today frequently comes out ahead of a theoretical, multi-year development outcome once the comparison is run honestly.