Event Parking Calculator

This calculator estimates how many parking spaces an event needs by first netting out guests who won't be driving alone: a transit/rideshare percentage removes people entirely from the parking count, and the remaining driving guests are divided by average vehicle occupancy (2.2 is the US average) to get a raw car count. A carpool rate then trims that further, but only at half its stated rate — the calculation assumes carpooling shifts some but not all of a group's cars, since carpool arrangements are rarely 100% consolidation. ADA-accessible space requirements follow the actual federal table, Table 208.2 of the U.S. Access Board's 2010 ADA Standards for Accessible Design: 1 accessible space for lots up to 25 total spaces, 2 up to 50, and so on up through 9 spaces at the 401-500 tier; above 500 the rule switches to 2% of the total, and above 1,000 it's a flat 20 plus 1 for every additional 100 spaces (or fraction of 100).

Physical area assumes 325 square feet per space, combining a standard 9-by-18-foot stall with its share of drive-aisle width — a number close to what real surface lots use per space including circulation. Rows are estimated at 50 spaces each (25 per side of a center aisle), and attendant staffing assumes 1 person can manage roughly 100 spaces during arrival and departure surges. A 12% overflow buffer is added on top of the base requirement, reflecting the common practice of reserving extra capacity beyond the calculated minimum for last-minute arrivals, vendors, or staff. This is a planning estimate, not a permit-ready site plan — actual municipal parking codes and ADA van-accessible space ratios should be confirmed with your local jurisdiction.