The Opportunity Zone Substantial Improvement Test for Existing Buildings

If a Qualified Opportunity Fund buys a building that was already in use in the zone, the building only counts as qualified property if the fund substantially improves it. For investors in renovation and conversion projects, this is often the test that decides the budget.

The free Opportunity Zone substantial improvement test calculator shows how much you need to add to the building's basis, and by when.

The rule

Within any 30-month period beginning after the building was acquired, additions to the building's basis must exceed its adjusted basis at the start of that period. In a zone made up entirely of a rural area, the bar is 50% of that basis instead of 100%.

What you enter

• Purchase price for land and building
• The share allocated to land, from your appraisal or cost allocation. Land is excluded from the test.
• Capitalized acquisition costs such as closing and title
• The date acquired. The 30-month period starts the next day.
• Depreciation before the period, usually $0
• Whether the zone is rural: a 2018 zone on the Notice 2025-50 rural list, or a 2027 zone comprised entirely of a rural area

Why the land split matters

Because land is excluded, the building's share of the price sets the target. A property where most of the price is land needs a smaller improvement budget than one where most of it is building. Get the allocation right before you underwrite.

Step by step: finding your improvement target

1. Open the substantial improvement calculator for Opportunity Zone buildings.
2. Enter the total purchase price.
3. Enter the land share from your appraisal or cost allocation.
4. Add capitalized acquisition costs.
5. Enter the acquisition date. The 30-month period starts the next day.
6. Choose whether the zone is entirely rural.
7. Read the basis you need to add, and the date by which you need to add it.

Hypothetical example: a townhouse conversion

Hypothetical example, for illustration only. A fund buys a $3,000,000 building in a non-rural zone, and the appraisal allocates 40% to land. Ignoring acquisition costs for simplicity, the building's share is $1,800,000. Under the 100% test, additions to the building's basis within the 30-month period must exceed that $1,800,000. If the same building were in a zone made up entirely of a rural area, the bar would be 50% of the building's basis. The calculator does this math with your real inputs, including acquisition costs.

Why land allocation drives the budget

Land is excluded from the test. In expensive markets, land is often a large share of the price, which can lower the improvement target relative to the purchase price. Get a supportable allocation; it affects both the target and depreciation.

Who uses it

• Developers and funds buying existing buildings for conversion.
• Agents listing older buildings in eligible or designated tracts to fund buyers.
• Investors checking a sponsor's renovation budget.

Common mistakes

• Counting land in the target.
• Starting the clock on the wrong day. The period begins after acquisition.
• Assuming the rural threshold applies without checking the tract. Use the tract lookup.
• Budgeting to the exact line. Additions must exceed the basis.

What the tool does not do

It does not decide whether a building is original use or used property, judge whether your costs are capitalizable, or confirm the zone's rural status for you. It takes your inputs and applies the 30-month test as the page describes it. Your adviser should confirm the facts behind each number, especially the land allocation and the acquisition date.

Questions to bring to your CPA or adviser

The tool gives you a starting point. Before you act, these are worth asking:

• Is the building original use, or must it be substantially improved?
• Is our land allocation supportable?
• Which acquisition costs are capitalized into basis?
• Is the zone entirely rural, so the 50% threshold applies?
• Does our construction schedule fit inside the 30-month period, with a buffer?
• How will we document additions to basis as they are made?
• What happens if the project runs over time or under budget?

Where this fits for luxury sellers and buyers

Historic townhouse conversions, older hotels turned into condos, and walk-ups rebuilt as high-end rentals can all land in Opportunity Zones. Agents who sell these properties to fund buyers, and investors underwriting them, can use the tool to see whether the renovation plan is big enough to qualify.

More free Opportunity Zone tools

This is one of several free planning tools in the Opportunity Zone tools library on Opportunity Zone Invest. To see whether a tract is rural, use the census tract lookup.

FAQ

Not tax advice. Tool outputs are estimates based on the figures you enter and current published rules. Investors get Opportunity Zone tax benefits only by investing through a Qualified Opportunity Fund. Talk to a CPA or tax attorney before you act.