BBQ Grill Size Calculator (cooking area for your party: cm² and square inches)

Understanding the BBQ grill size calculator — concept and principle

This calculator estimates how much grill cooking area you need for a party, in cm² and square inches, from the number of people, portions, the size of each item and how many rounds of cooking you plan. It helps when buying or renting a grill.

Items × space each: with the default inputs the result is 1,764 cm² (≈ 273 in² · 42 cm square).

How it is calculated

Items in total = people × portions per person, rounded up

Items at once = items ÷ rounds, rounded up

Cooking area = items at once × (item diameter + gap)²

Square inches = cm² ÷ 6.4516; square grill side = √area

The principle

Each round item, such as a burger, takes up a square on the grate whose side is its diameter plus the gap you leave around it. Multiplying by the number of items cooked at once gives the area. Grills are sold by primary cooking area in square inches; warming racks do not count.

Worked example

Default inputs: 12 people, 1.5 portions each, 11.5 cm items, 2.5 cm gap, 2 rounds.

Items = 12 × 1.5 = 18; at once = 18 ÷ 2 = 9.
Area = 9 × (11.5 + 2.5)² = 9 × 196 = 1,764 cm².
In square inches = 1,764 ÷ 6.4516 = 273 in².
Square grill side = √1,764 = 42 cm.

Each point is the calculator re-run with only “Size of one item, e.g. patty diameter (cm)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Size of one item, e.g. patty diameter (cm)	Cooking area needed (cm²)
2.88	260
5.75	613
8.62	1,114
11.5	1,764
14.4	2,563
17.2	3,511
23	5,852

How to read the result

For two-zone cooking, with one side hot and one side cooler for finished food and flare-ups, choose a grill about a quarter larger than the result. Long items such as sausages and skewers take less width but more length. More rounds mean a smaller grill but longer cooking time.

Common mistakes

Counting the warming rack as cooking area.
Forgetting space for vegetables and sides.
Packing items edge to edge, which makes turning hard and causes flare-ups.

Keep in mind: Use grills outdoors only, away from buildings, and never leave a lit grill unattended.

Frequently asked questions

How big a grill for 10 people?

With burgers in two rounds, roughly 1,500 cm² (about 230 in²) of primary area.

Does a round grill have the same area as a square one?

Not for the same width; a round grate of diameter D has about 79% of the area of a square of side D.

How much gap should I leave?

About 2–3 cm lets you turn food and lets heat circulate.

Sources: 1 in = 2.54 cm exactly (NIST Special Publication 811); square-cell grid geometry

Checked 9 Nov 2026. Grid geometry (square cell of side d + gap per item); 1 in = 2.54 cm exactly. Portions, item size and gap are example values.

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