Theater Calculators

TV mounting & DIY

AV Rack U-Space Calculator

1U is 44.45 mm. Leave empty U as chimneys. A 9.4-ch AVR is often 4U plus a 1U gap.

Inputs

Units
U

Box height in mm ÷ 44.45, rounded up.

U
U
U
U

Counted once for each of AVR, disc and network that is not zero.

Results

Gear U
8
Vent U
3
Cabinet U to buy
11

The Result is indicative and educational. It does not constitute a design, a technical opinion or medical advice and does not replace calculations or verification by a person with the appropriate qualifications and authorisations. Before purchase, installation or use in practice – in particular in electrical installations – the Result should be verified by a qualified specialist. Details: Terms of Service, point 4.

Example products

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Calculation method

Used U = sum of gear. Vent U = vent-each × the hot groups in use (AVR/amp, disc, network; at most 3). Rack = used + vent, rounded up.

Exact formula

1U = 44.45 mm. Rack = ceil(ΣU + k·v), k = AVR, disc and network groups above zero. Limits: one gap per group (a second amp in the same group gets none), no depth, no weight, no IEC inlet count.

Frequently asked questions

Is a 2U AVR really 2U?

Check the manual. Handles and feet can steal another U in a closed box.

Wheels?

A 12U on casters still needs the depth for the IEC power leads at the back.

Wall cabinet?

Same U math. Heat is worse — add the vent U, not subtract.

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