How many parking spaces a commercial building requires is set by the local zoning code where the property sits, and the number depends on what the building is used for and how large it is. A 20,000-square-foot office might need 60 to 80 spaces in one city and none in another. Layered on top of whatever the local count comes out to, federal law under the Americans with Disabilities Act dictates how many of those spaces must be accessible. There is no national minimum for the total.
Where the Number Comes From
Parking counts live inside municipal or county zoning ordinances, sometimes called land development codes. The local planning or community development department writes the rules, enforces them during permitting, and can grant exceptions. Look for the “off-street parking” chapter of your jurisdiction’s zoning code, usually posted on the city or county website.
A wrinkle worth checking first: several states now prohibit cities from imposing minimum parking requirements on developments near public transit, typically within a half-mile of a major stop. If your site is close to transit, your local minimum may legally be zero even if the code still lists a number. Colorado removed minimums for various residential development types in 2025, and Illinois enacted a similar law effective in 2026 covering half-mile transit zones. These preemption laws still allow local governments to set parking maximums or require bicycle parking.
How Use Category Drives the Ratio
The single biggest factor in your count is what happens inside the building. A 200-seat restaurant generates far more parking demand per hour than a 200-seat office, because diners cycle through while office workers park once and stay all day. Codes reflect that by giving each land use its own formula.
Typical categories and ranges:
- General office: usually 3 to 5 spaces per 1,000 square feet of gross floor area.
- Retail and shopping centers: often 4 to 5 spaces per 1,000 square feet, reflecting customer turnover.
- Restaurants and bars: tied to seating capacity, commonly one space per three or four seats.
- Medical and dental offices: often 4 to 6 spaces per 1,000 square feet, sometimes calculated per exam room.
- Theaters and assembly halls: based on fixed seats or maximum occupancy rather than floor area.
- Industrial and manufacturing: often tied to employee headcount or a lower per-square-foot ratio.
Ratios vary widely between jurisdictions. A suburban city with no transit may require 5 office spaces per 1,000 square feet, while an urban core with rail service might require 3 or fewer. Pull the exact ratio from your local code rather than relying on rules of thumb.
Running the Calculation
Once you have the ratio, multiply the building’s gross floor area (in thousands of square feet) by that ratio. A 20,000-square-foot office in a jurisdiction requiring 4 spaces per 1,000 square feet needs 80 spaces. The same building used as retail at 5 per 1,000 needs 100.
For uses measured by something other than floor area, plug in the relevant unit. A 150-seat restaurant at one space per three seats needs 50 spaces. A 400-seat theater at the same ratio needs about 134. When the formula produces a fraction, most codes round up.
Read how your code defines “gross floor area.” Some jurisdictions exclude storage rooms, mechanical closets, or interior hallways from the calculation; others count everything within the exterior walls. That definitional difference can swing your required count by 10 to 15 percent on a large building.
Mixed-Use Buildings
When one building contains more than one use, most codes require you to calculate parking for each use separately and add the totals. A building with 10,000 square feet of ground-floor retail and 20,000 square feet of upper-floor office gets calculated as two separate demands.
That additive approach often produces unrealistically high counts, because uses rarely peak at the same time. Many jurisdictions offer a shared parking reduction. If offices fill their spaces during the day while a ground-floor restaurant peaks in the evening, the code may let you overlap a percentage of those spaces rather than building both sets. Getting the reduction usually requires a parking study showing combined peak demand is lower than the sum, plus approval from the planning director or zoning board.
ADA Accessible Space Minimums
Whatever your local total works out to, federal law governs how many of those spaces must be accessible. The 2010 ADA Standards for Accessible Design set the following minimums, calculated per parking structure rather than across the whole site. A property with both a surface lot and a garage must meet the minimums for each independently.1U.S. Department of Justice. Accessible Parking Spaces – ADA.gov
- 1 to 25 total spaces: 1 accessible space
- 26 to 50: 2
- 51 to 75: 3
- 76 to 100: 4
- 101 to 150: 5
- 151 to 200: 6
- 201 to 300: 7
- 301 to 400: 8
- 401 to 500: 9
- 501 to 1,000: 2 percent of the total
- Over 1,000: 20, plus 1 for each 100 (or fraction of 100) over 1,000
Van-Accessible Spaces
At least one of every six accessible spaces (or fraction of six) must be van-accessible. A lot requiring six accessible spaces must include at least one van space. Van-accessible spaces must be at least 132 inches wide with a 60-inch access aisle. Standard accessible spaces must be at least 96 inches wide, with the same 60-inch aisle.2U.S. Access Board. Chapter 5: Parking Spaces
Location, Signage, and Surface
Accessible spaces must sit on the shortest accessible route to the building entrance relative to other spaces in the lot. Each space needs a vertical sign displaying the international symbol of accessibility, mounted so the bottom edge is at least 60 inches above the ground. Van-accessible spaces need a second sign stating they are van-accessible. The surface must be firm, stable, slip-resistant, and have no more than a 2.08 percent slope in any direction.1U.S. Department of Justice. Accessible Parking Spaces – ADA.gov
EV Charging in the Parking Count
A growing number of jurisdictions now require new commercial buildings to include electric vehicle charging infrastructure. At least seven states have enacted some form of EV-readiness requirement for commercial construction, from pre-wiring a percentage of spaces to installing active stations. California requires dedicated EV spaces starting at 10 total parking spaces, scaling so that lots with 200 or more spaces must designate at least 6 percent for EVs. Massachusetts requires at least 20 percent of spaces in lots with 10 or more to be EV-ready.
Even where nothing is mandated, a federal tax credit is available. Businesses that install qualified charging equipment can claim a credit equal to 6 percent of the cost per port, up to $100,000 per unit, for property placed in service through June 30, 2026. Meeting prevailing wage and apprenticeship requirements raises the credit to 30 percent with the same cap.3Internal Revenue Service. Alternative Fuel Vehicle Refueling Property Credit
Change of Use and Expansions
One of the most common parking surprises hits when an existing building changes hands and the new tenant has a different use. Converting a 10,000-square-foot office to a restaurant can double or triple the parking requirement. Most codes require the new use to meet its own standard, and if the existing lot falls short, the tenant cannot get a certificate of occupancy until the shortfall is resolved.
Expansions work the same way. Adding square footage typically triggers additional parking for the net increase. If you’re evaluating a commercial property for purchase or lease, check the parking requirement for your intended use before signing. Discovering a 30-space deficit after closing is an expensive problem with limited solutions.
When the Lot Can’t Hold the Required Count
Physical constraints, tight lots, and historic buildings sometimes make full on-site compliance impossible. Most codes offer at least one alternative path.
Zoning Variances
A variance is a formal request for the zoning board to waive or reduce the standard. You must show that something unique about the site (size, shape, topography, or location) makes strict compliance impractical in a way other nearby properties don’t face. Variances aren’t granted just because compliance is expensive. Filing fees run from a few hundred to several thousand dollars, and the process includes a public hearing where neighbors can object.
Shared Parking Agreements
If a neighboring property has surplus parking during your peak hours, a shared arrangement can satisfy the code without building new spaces. This works best when the two uses operate on opposite schedules, like an office that empties at 5 p.m. paired with a restaurant that fills at 6 p.m. Most jurisdictions require a written, recorded agreement between owners and often a parking study showing combined demand won’t exceed the shared supply at any point in the day.
In-Lieu Fees
Some cities let developers pay a per-space fee instead of building the required parking. The money goes into a municipal fund used to build or maintain public parking. Fees vary widely: studies have found per-space fees from roughly $2,000 to over $27,000, with many cities clustering around $10,000 to $15,000. This option is typically available only in downtown or commercial districts where public parking already exists or is planned.
What Happens If You Come Up Short
Ignoring the requirement can halt a project entirely. The most immediate consequence is that the building department refuses to issue a certificate of occupancy, so you cannot legally open. For projects under construction, the zoning administrator can issue a stop-work order until the deficiency is corrected.
If a violation is discovered after occupancy, enforcement escalates. Many jurisdictions treat each day the violation continues as a separate offense with daily civil penalties that accumulate until fixed. In extreme cases, the jurisdiction can revoke the permit or seek a court order requiring compliance at the owner’s expense, with those costs becoming a lien on the property. Getting the count right during design is almost always cheaper than fixing it after the inspector shows up.