How to use the required parking spaces calculator
There is no federal or statewide minimum parking standard in the United States. Off street parking counts are set by each municipality in its own zoning ordinance, which is why the same office building can need a very different number of spaces two towns apart. Just as importantly, a growing number of cities including Buffalo, Minneapolis, San Jose and Austin have removed parking minimums entirely, so the first question is always whether a minimum still applies at your address.
The ratios in this tool are the customary values that appear in many ordinances, such as one space per 300 square feet of office, one per 250 for retail and one per 1,000 for warehouse space. Treat them as a planning estimate for early massing studies, then read the actual ordinance text, because many codes measure net rather than gross area, exempt mechanical space, or set the ratio by seats, beds or employees instead of area.
The accessible parking figure is different. Section 208.2 of the 2010 ADA Standards for Accessible Design is a federal requirement that applies to each parking facility regardless of local zoning, and this tool applies that table directly. At least one in every six accessible spaces must be van accessible, and separate scoping applies to hospital outpatient and rehabilitation facilities. Confirm the final counts with the zoning administrator and your architect before submitting for permit.
Frequently asked questions
Then the zoning ratio no longer sets a floor and you can build the amount the project actually needs. The ADA scoping still applies to whatever parking you do build, and lenders or tenants may impose their own parking ratios by lease.
Most ordinances require each use to be calculated separately and then added, though many allow shared parking reductions where peak demands do not overlap. Run each use through the tool and add the results for a first estimate.