This planner works through the same trade-off a lot designer does: steeper stall angles need less room to maneuver, so more rows fit — but each stall takes up more curb length. Change any value below and the layout updates.

Lot width (ft)

Lot depth (ft)

Stall width (ft)

Stall length (ft)

Stall angle

Aisle traffic flow

90° parking always needs two-way aisles, since angled stalls can't be entered against the flow.

Aisle width (ft)

Filled in from the angle and traffic flow above — edit it directly if your site needs something different.

Connector drive aisle (ft)

Runs the full depth of the lot along one side, two-way, so every row's aisle actually connects through to the entrance instead of dead-ending.

Connector runs along

Entrance / exit at

Tests every stall angle against both traffic flows for your current lot and stall size, and applies whichever combination fits the most cars.

Stalls Drive aisle Unused depth

How this is calculated

The planner tiles the lot with rows of stalls served by drive aisles, stacking as many double-loaded rows (stalls on both sides of an aisle) as the depth allows, then adding one single row against the far edge if there's room left over. A connector aisle runs the full depth of the lot along one side and meets every row's aisle, so the entrance at the bottom actually has a route to each row — without it, rows in the middle of the lot would have no way in or out.

Angled stalls take more curb length per car (width ÷ sinθ) but a shallower row depth (length × sinθ), which is why a shallower angle can sometimes fit more cars overall in a shallow lot.
"Auto" tests 90°, 60°, 45°, and 30° with the recommended aisle width for each, and keeps whichever produces the most stalls.
The connector aisle takes width away from the parking rows themselves, so a wider one means fewer stalls per row — the diagram and totals reflect that trade-off.
Space efficiency is the lot area divided by the stall count — lower means each parked car is costing you less pavement.

This is a planning estimate, not a stamped site plan. It doesn't account for ADA-accessible stall requirements, curb radii, drainage, landscaping islands, fire-lane access, or local zoning code — get those checked by a civil engineer or your local planning office before construction.

Design your parking lot

How this is calculated