Theater Calculators

Signal, cables & storage

HDMI Bandwidth Calculator

Payload ≈ width × height × refresh × bits × 3 channels × chroma × (1+blanking). HDMI 2.0 TMDS usable payload is ~14.4 Gbit/s (8b/10b of 18); HDMI 2.1 FRL is 48.

Inputs

Units
px
px
Hz
bit

1 = 4:4:4, 0.67 ≈ 4:2:2, 0.5 = 4:2:0.

CTA-861 TV timings: ≈0.19 at 60/120 Hz, 0.43 at 50/100 Hz, 0.49 at 24 Hz; PC reduced blanking ≈0.05–0.1.

Results

Payload
14.21Gbit/s
Fits HDMI 2.0 TMDS (14.4)?
Yes
Fits HDMI 2.1 (48)?
Yes

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.

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Calculation method

Gbit/s = N_x N_y f B 3 χ (1+b) / 10^9. HDMI 2.0 TMDS usable payload is ~14.4 Gbit/s (8b/10b of 18); HDMI 2.1 FRL is 48.

Exact formula

Gbps = W·H·f·B·3·χ·(1+b)/1e9. HDMI 2.0 OK if ≤14.4 (TMDS 8b/10b of 18; TMDS sends blanking at the pixel rate). HDMI 2.1 OK if ≤48: FRL compresses horizontal blanking, which for CTA 60/120 Hz timings roughly offsets its ~13% loss to 16b/18b coding and FEC. Limits: no DSC, no 4:2:2 packing quirks, no cable length, blanking is typed in rather than read from a CTA-861 or CVT timing, and with PC reduced blanking the 2.1 check is optimistic above ~41 Gbit/s.

HDMI 2.0 is 14.4 Gbps usable, not 18

Marketing 18 Gbps is the TMDS line rate. After 8b/10b the payload budget is 14.4 Gbps. 4K60 10-bit 4:4:4 with blanking does not fit HDMI 2.0 on this page even if a cable is labelled 18 Gbps.

Why HDMI 2.1 is compared to the full 48 Gbps

FRL loses about 13% of its 48 Gbps to 16b/18b coding and Reed-Solomon FEC, but unlike TMDS it does not send horizontal blanking at the pixel rate; it compresses it into a few characters. For CTA TV timings at 60 or 120 Hz the two effects nearly cancel, so the payload with blanking against 48 lands within about 3% of the spec’s FRL capacity check: 4K120 12-bit 4:4:4 (about 43 Gbps) fits, 4K144 12-bit (about 51) does not. With PC reduced blanking or 0% the check is optimistic, so treat anything above about 41 Gbps as needing DSC.

Frequently asked questions

Is 4K/60 always 2.0?

At the CTA-861 timing (~19% blanking), 8-bit 4:4:4 needs 14.26 Gbit/s and just fits 14.4 Gbit/s TMDS. 10-bit 4:4:4 or 4K/120 does not; 10-bit HDR at 4K60 fits only as 4:2:2 or 4:2:0.

What is DSC?

Display Stream Compression can pack more into 2.1. This tool is uncompressed payload.

Long cable?

Active or fibre after ~5–8 m. Bandwidth math does not replace a certified cable.

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