{
    "name": "Event Seating Capacity Calculator",
    "url": "https://calculators.geekmidst.com/calculators/event-seating-capacity-calculator",
    "markdown": "https://calculators.geekmidst.com/calculators/event-seating-capacity-calculator.md",
    "category": "Everyday tools",
    "description": "Estimate how many chairs fit in a room in theatre-style rows from its size, seat width, row spacing, aisles and the space kept clear at the front and back.",
    "summary": "Theatre-style capacity is seats per row times rows: the width left after aisles divided by the seat width, and the depth left after clearances divided by the row spacing.",
    "also_called": [
        "Chair layout calculator",
        "Theatre-style capacity calculator"
    ],
    "applies_to": "Worldwide",
    "last_updated": "2026-10-29",
    "computation": "Results are computed in the visitor’s browser on the HTML page. This API describes the calculator; it does not compute results.",
    "inputs": [
        {
            "name": "room_width",
            "label": "Room width (across the rows)",
            "type": "number",
            "default": "20"
        },
        {
            "name": "room_depth",
            "label": "Room depth (front to back)",
            "type": "number",
            "default": "30"
        },
        {
            "name": "front",
            "label": "Stage and front clearance",
            "type": "number",
            "default": "5",
            "optional": true
        },
        {
            "name": "rear",
            "label": "Rear clearance (cross aisle)",
            "type": "number",
            "default": "2",
            "optional": true
        },
        {
            "name": "seat_width",
            "label": "Seat width, centre to centre",
            "type": "number",
            "default": "0.5"
        },
        {
            "name": "row_pitch",
            "label": "Row spacing, back to back",
            "type": "number",
            "default": "0.9"
        },
        {
            "name": "aisles",
            "label": "Number of aisles",
            "type": "number",
            "default": "2",
            "optional": true
        },
        {
            "name": "aisle_width",
            "label": "Width of each aisle",
            "type": "number",
            "default": "1.2",
            "optional": true
        }
    ],
    "outputs": [
        {
            "key": "seats",
            "label": "Seats that fit",
            "format": "integer"
        },
        {
            "key": "per_row",
            "label": "Seats per row",
            "format": "integer"
        },
        {
            "key": "rows",
            "label": "Rows",
            "format": "integer"
        },
        {
            "key": "area_per_seat",
            "label": "Room area per seat (your unit squared)",
            "format": "number"
        },
        {
            "key": "seated_share",
            "label": "Share of the floor used by seating blocks",
            "format": "percent"
        }
    ],
    "formula": {
        "text": "Seats per row = ⌊(Width − Aisles × Aisle width) ÷ Seat width⌋;  Rows = ⌊(Depth − Front − Rear) ÷ Row spacing⌋;  Seats = Seats per row × Rows",
        "variables": {
            "Seat width": "chair width plus any gap, centre to centre",
            "Row spacing": "distance from the back of one row to the back of the next"
        }
    },
    "worked_example": {
        "inputs": {
            "room_width": "20",
            "room_depth": "30",
            "front": "5",
            "rear": "2",
            "seat_width": "0.5",
            "row_pitch": "0.9",
            "aisles": "2",
            "aisle_width": "1.2"
        },
        "steps": [
            "Width for seats = 20 − 2 × 1.2 = 17.6 m; 17.6 ÷ 0.5 = 35.2, so 35 per row.",
            "Depth for rows = 30 − 5 − 2 = 23 m; 23 ÷ 0.9 = 25.6, so 25 rows.",
            "Seats = 35 × 25 = 875."
        ],
        "result": "A 20 × 30 m room with a 5 m stage zone, two 1.2 m aisles, 0.5 m chairs and 0.9 m rows seats 875 people theatre-style."
    },
    "interpretation": "This is a geometric fit. The number you may actually admit is the lower of this figure and the legal occupancy limit set for the room by the fire or building authority.",
    "assumptions": [
        "A rectangular room with straight rows and aisles running front to back.",
        "All lengths are in the same unit."
    ],
    "limitations": [
        "Fire codes also limit seats per row between aisles, exit widths and travel distances; these are not checked here.",
        "Pillars, AV desks and wheelchair spaces must be subtracted separately."
    ],
    "rules": null,
    "faqs": [
        {
            "question": "How much space per person for theatre seating?",
            "answer": "The answer here shows it for your layout. Planners often work from a figure per person, but codes and venues differ, so use your own measurements."
        },
        {
            "question": "Does this give the legal capacity?",
            "answer": "No. Only the authority that licenses the venue sets its maximum occupancy."
        }
    ],
    "sources": [],
    "related": [
        {
            "name": "Venue Occupancy Calculator",
            "url": "https://calculators.geekmidst.com/calculators/venue-occupancy-calculator"
        },
        {
            "name": "Area Calculator",
            "url": "https://calculators.geekmidst.com/calculators/area-calculator"
        },
        {
            "name": "Length Converter",
            "url": "https://calculators.geekmidst.com/calculators/length-converter"
        }
    ],
    "disclaimer": null,
    "publisher": "GM¹X CalcVerse"
}