Resource search

Search DataDrivenAEC

Type at least two characters to search.

Looking for live projects? Explore open projects or browse the feed.

Open the full search page →

FreeZoning / local ratioArithmetic only

Methodology

Parking Supply Scenario Calculator

There is no single IBC or ITE table that establishes a national minimum number of parking spaces for every development. Use a ratio from the adopted local zoning ordinance, an approved parking study, or another source you have verified for the project.

Who it's for: architects and planners who already have a verified spaces-per-unit ratio (from the local zoning ordinance or an approved parking study) and need the arithmetic for a project quantity, at feasibility or permit review.

Use the right source for each question

  • Required parking supply: the adopted municipal or other local zoning ordinance.
  • Estimated parking demand: a project-specific study or ITE parking-generation data, where appropriate.
  • Parking-garage construction: IBC Section 406 and the locally adopted building code.
  • Accessible parking: the applicable accessibility law/code, including special facility rules.

Methodology reviewed 31 August 2026. Local requirements remain user supplied.

How to use this calculator

1
Enter the project quantity
For example, dwelling units, gross square footage, or seats.
2
Enter the ratio and divisor from your verified source
Use a spaces-per-unit ratio from the adopted local zoning ordinance or an approved parking study, and the basis-unit divisor it is stated against (1 for "per unit," 1,000 for a ratio stated per 1,000 ft²).
3
Read the scenario result
The result is the project quantity × ratio ÷ divisor, rounded up — a planning scenario, not a code-required minimum or maximum.

The formula

Scenario spaces = ceiling(project quantity × spaces-per-basis-unit ratio ÷ basis-unit divisor). There is no single IBC or ITE table that establishes a national minimum number of parking spaces; the ratio itself must come from the adopted local zoning ordinance or an approved parking study you supply.

Worked example

Example
45 dwelling units at a verified ratio of 1.25 spaces per dwelling unit (divisor 1): 45 × 1.25 ÷ 1 = 56.25, rounded up to 57 spaces.

When this estimate will be off

  • This is a planning scenario, not a code-required minimum or maximum.
  • The required ratio itself comes from the adopted local zoning ordinance, not from this tool — it only divides the project quantity by the basis-unit divisor and multiplies by the ratio you supply.
  • Does not include accessible or EV spaces, shared-parking rules, reductions, caps, loading, or bicycle parking — confirm those with the adopted local requirements.
  • IBC Section 406 covers parking-garage construction, not the number of spaces required, and ITE parking-generation data measures demand, not a zoning minimum — use the source that matches the question being asked.

Frequently asked questions

A common mistake: This is a planning scenario, not a code-required minimum or maximum.

No. It only divides your project quantity by the basis-unit divisor and multiplies by the ratio you supply. The required ratio itself comes from the adopted local zoning ordinance, not from this tool.

IBC Section 406 covers parking-garage construction, not the number of spaces required — and ITE parking-generation data measures demand, not a zoning minimum. Use the source that matches the question you're actually asking, as listed above.

No. Accessible parking counts come from the applicable accessibility law/code and are not added by this scenario.

The scenario rounds the raw quantity × ratio ÷ divisor result upward, consistent with how a required or planned space count is normally expressed.

This free Parking Supply Scenario Calculator is built and maintained by DataDrivenAEC, using the relevant codes and standards. It does not substitute for professional judgment.