DISCLAIMER: THIS IS NOT PERFECT. I'm going on listed attendance figures and listed capacities for each arena. I realize the numbers vary based on camera positions, event setup, aesthetic purposes, and many other purposes.

This is just to give somewhat of an idea of how each UFC event did based on attendance vs. capacity. Now very few arenas have dedicated capacity for MMA events. Many do, however, for concerts, or more specifically, center-stage concerts. Again, it's not perfect, but it's the closest I can find to the approximate size needed for the Octagon, judges, commentary, etc... In some cases, some offer boxing or wrestling capacities, which is just about perfect as far as layout goes.

Not 100% scientific, but more just to give an idea.

UFC 142: 12,500

HSBC Arena, Rio de Janeiro Capacity: 18,000 for concerts.

% Filled: 69.4

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UFC on FX: Guillard vs. Miller: 7.728

Bridgestone Arena, Nashville Capacity: 20,000 for center stage concerts.

% Filled: 38.6

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UFC on FOX: Evans vs. Davis: 16,693

United Center, Chicago Capacity: 23,500 for concerts

% Filled: 71.0

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UFC 143: 9,015

Mandalay Bay, Las Vegas Capacity: 12,000

% Filled: 75.1

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UFC on Fuel: Sanchez vs. Ellenberger: 7,120

Omaha Civic Auditorium Capacity: 10,960 for concerts

% Filled: 64.9

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UFC 144: 20,000

Saitama Super Arena Capacity: Listed at 5,000-37,000, but Yarennoka 2007, their giant New Year's Eve Show and subsiquent Dynamite! New Year's Eve Shows did anywhere between 25-27, except for 2008, which apparently did 45. I'll settle with around 27.

% Filled: 74.1

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UFC on FX: Alves vs. Kampmann: 14,537

Allphones Arena, Sydney, Capacity: 21,000

% Filled: 69.2

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UFC on Fuel: Gustafsson vs. Silva: 15,428

Ericsson Globe Arena, Stockholm, Capacity: 16,000 for concerts

% Filled: 96.4

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UFC 145: 15,545

Philips Arena, Atlanta, Capacity: 21,000 for concerts

% Filled: 74.0

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UFC on FOX: Diaz vs. Miller: 10,788

IZOD Center, East Rutherford, Capacity: 20,000 for Concerts

% Filled: 53.9%

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UFC on Fuel: Korean Zombie vs. Poirer: 6,668

Patriot Center, Fairfax, Capacity: 10,000 for basketball, so we'll say about 12,500 for concerts.

% Filled: 53.3

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UFC 146: 14,674

MGM Grand Capacity: 16,800

% Filled: 87.3

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The Ultimate Fighter 15 Finale: 1,628

Pearl at the Palms Capacity: 2,500

% Filled: 65.1

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UFC on FX: Johnson vs. McCall: 6,635

BankAtlantic Center, Miami Area Capacity: 22,457 for center-stage concerts

% Filled: 29.5

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UFC on FX: Guida vs. Maynard: 4,652

Revel Casino Ovation Hall, Atlantic City Capacity: 5,500

% Filled: 84.6

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UFC 147: 16,643

Felipe Drummond Stadium, Belo Horizonte Capacity: 25,000

% Filled: 66.6

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UFC 148: 15,104

MGM Grand Capacity: 16,800

% Filled: 89.9

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UFC on Fuel: Munoz vs. Weidman: 4,250

HP Pavilion Capacity: 18,300 for wrestling

% Filled: 23.2

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UFC 149: 16,089

Scotiabank Saddledome, Calgary Capacity: 19,289 for hockey, so probably around 21,000

% Filled: 76.6

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UFC on FOX: Shogun vs. Vera: 16,080

Staples Center Capacity: 21,000 for boxing/wrestling

% Filled: 76.6

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UFC 150: 13,027

Pepsi Center, Denver, Capacity: 20,000 for concerts

% Filled: 65.1

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UFC 152: 16,800

Air Canada Centre, Toronto, Capacity: 19,800 for concerts

% Filled: 84.8

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UFC on Fuel: Struve vs. Miocic: 7,241

Capital FM Arena, Nottingham, Capacity: 10,000

% Filled: 72.4

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UFC on FX: Browne vs. Bigfoot: 7,049

Target Center, Minneapolis, Capacity: 19,356

% Filled: 36.4