Parking Lot Capacity Calculator
How many car spaces a site can hold from its area and the bay layout — 90°, 60°, 45° or parallel — allowing for aisles, circulation and the accessible bays required.
Each parked car needs its bay plus a share of the aisle that serves it: about 25–28 m² all-in for 90° bays on a double-loaded aisle, more for angled bays that need one-way aisles, and around 20 m² for parallel parking along a kerb.
How the parking lot capacity calculator works
Each parked car needs its bay plus a share of the aisle that serves it: about 25–28 m² all-in for 90° bays on a double-loaded aisle, more for angled bays that need one-way aisles, and around 20 m² for parallel parking along a kerb. Take off the circulation, ramps and landscaping that do not park cars, divide by the area per bay, and set aside the accessible bays at the required percentage.
Formula: bays = usable area × (1 − circulation) ÷ area per bay; accessible = ceil(bays × rate)
Worked examples
| Inputs | Car spaces | Note |
|---|---|---|
| 5,000 m² at 90°, 12% circulation | 162 | 162 spaces, 4 accessible |
| Same site with 45° bays | 133 | 133 spaces |
| A 1,200 m² strip, parallel | 51 | 51 spaces |
FAQFrequently asked questions
Why 27 m² for a 2.5 × 5.4 m bay?
The bay itself is 13.5 m², but each car also needs half of a 6.5 m two-way aisle (8 m²) and a share of the end turns; 25–28 m² per bay is what real 90° car parks achieve. Small-car bays and one-way angled layouts change it.
Which layout holds the most?
90° bays on double-loaded aisles, almost always. Angled bays are easier to enter and suit one-way circulation but cost 10–20% more area; parallel bays only make sense along a lane that exists anyway.
How many accessible bays?
It depends on the building code and use — commonly 1–3% of spaces, with a minimum of one, and more for hospitals and aged care. Each takes about 1.5 times a standard bay because of the shared zone beside it.
What about multi-storey or basement car parks?
Ramps, columns and cores take more: allow 20–30% loss rather than 12%, and about 30–35 m² per bay all-in. Mechanical stackers change the arithmetic entirely.
Where these figures come from
- UN-Habitat — Urban Indicators Guidelines — density, green space and public space benchmarks
- World Health Organization — Urban green spaces — the 9 m² per person minimum
- ITE — Parking Generation Manual — parking demand rates by land use
- Office for National Statistics — Population estimates — the UK's national statistics agency
Last checked: September 2026. Default per-capita rates are mid-range figures from national statistical agencies and utility reports; every one is an input you should replace with the local figure.