Parking Ratio Calculator (spaces per 1,000 sq ft or per 100 m²)

Understanding the parking ratio calculator — concept and principle

A parking ratio compares the number of parking spaces with the size of a building. Developers, leasing agents and planners use it to check whether a site meets zoning requirements or market expectations. This calculator converts between spaces per 1,000 square feet, spaces per 100 m² and floor area per space, and checks a target ratio.

120 spaces on 40,000 sq ft is exactly 3 per 1,000 sq ft, about 3.23 per 100 m², meeting the target with no surplus.

How it is calculated

Spaces per 1,000 sq ft = spaces ÷ (floor area in sq ft ÷ 1,000).
Spaces per 100 m² = spaces ÷ (floor area in m² ÷ 100), with 1 sq ft = 0.09290304 m².
Floor area per space = floor area ÷ spaces.
Spaces required = ratio × floor area ÷ 1,000 (or ÷ 100 for m²), rounded up to a whole space.
Surplus or shortfall = spaces − spaces required.

The principle

Parking demand grows with the size and use of a building, so codes and leasing practice express it as a rate per unit of floor area. In the US the convention is spaces per 1,000 sq ft; many other codes, including Korea's, state the floor area served by one space (for example one space per 150 m²). Both describe the same relationship, just inverted. Rounding up ensures a requirement is always met with whole spaces.

Worked example

Default inputs: 120 spaces, 40,000 sq ft, target ratio 3 per 1,000 sq ft.

Spaces per 1,000 sq ft = 120 ÷ 40 = 3.
Floor area in m² = 40,000 × 0.09290304 ≈ 3,716 m²; spaces per 100 m² = 120 ÷ 37.16 ≈ 3.23.
Floor area per space = 40,000 ÷ 120 ≈ 333 sq ft, or about 31 m².
Required at 3 per 1,000 = 3 × 40 = 120 spaces.
Surplus or shortfall = 120 − 120 = 0.

Each point is the calculator re-run with only “Building floor area” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Building floor area	Spaces per 1,000 sq ft
10,000	12
20,000	6
30,000	4
40,000	3
50,000	2.4
60,000	2
80,000	1.5

How to read the result

Compare the ratio with the local zoning code for the building's use and with what tenants in that market expect. Requirements differ by use (office, retail, housing, medical) and by which floor area counts (gross, net or leasable). A ratio well above the requirement uses land and money that could serve other purposes; one below it may limit tenants.

Common mistakes

Using gross area when the code specifies net or leasable area.
Applying an office ratio to a mixed-use building.
Forgetting accessible-parking requirements, which are set separately.
Rounding down a required number of spaces.

Keep in mind: Parking rules vary by jurisdiction, use and zone. Check the local code and consult a qualified professional before designing or permitting a project.

Frequently asked questions

What is a typical office parking ratio?

It varies widely by city and transit access; check local codes and comparable buildings rather than relying on a single figure.

How do I convert spaces per 1,000 sq ft to spaces per 100 m²?

Multiply by about 1.076, because 100 m² ≈ 1,076 sq ft.

Does the ratio include accessible spaces?

Accessible spaces are usually part of the total but have their own minimum counts under accessibility rules.

Sources: Institute of Transportation Engineers, Parking Generation Manual · 주차장법 시행령 별표 1 (부설주차장의 설치대상 시설물 종류 및 설치기준)

Checked 9 Nov 2026. Parking ratio = spaces ÷ floor area (per 1,000 sq ft or per 100 m²): standard real-estate definition. 1 ft = 0.3048 m exactly, so 1 sq ft = 0.09290304 m².

Your numbers