HDMI Bandwidth Calculator

How does HDMI bandwidth work?

HDMI (High-Definition Multimedia Interface) transmits video and audio data over a set of high-speed serial data channels. In HDMI versions 1.0 through 2.0, three TMDS (Transition-Minimized Differential Signaling) data channels carry pixel data alongside a separate clock channel. Starting with HDMI 2.1, the interface switches to FRL (Fixed Rate Link) mode with four data channels and a more efficient encoding scheme, dramatically increasing the available bandwidth.

The raw transmission rate does not equal the usable data rate because of encoding overhead. TMDS-based HDMI versions use 8b/10b encoding, where 10 transmitted bits carry only 8 bits of actual data — an 80% efficiency. HDMI 2.1 and 2.2 use 16b/18b encoding with an effective efficiency of 87.5% after accounting for link-layer overhead. The resulting data rate determines how many pixels per second the connection can deliver.

Whether a particular resolution and refresh rate combination is achievable depends on the HDMI version's data rate, the color format (RGB, YCbCr 4:4:4, 4:2:2, or 4:2:0), and the color depth (bits per component). Higher resolutions, faster refresh rates, and richer color all demand more bandwidth. Understanding these limits helps avoid buying a monitor or cable that your HDMI port cannot fully drive.

Tool description

This calculator determines the maximum refresh rate for any combination of HDMI version, resolution, color format, and color depth. It displays a feasibility table for common refresh rates (60, 120, 144, 165, 240, and 360 Hz), showing whether each is supported and what percentage of the available bandwidth it consumes. All calculations use official HDMI specification data rates and include CVT-RBv2 blanking interval overhead.

How it works

The calculator follows these steps:

1. Look up available data rate: Each HDMI version has a fixed maximum data rate defined by its specification — from 3.96 Gbit/s (HDMI 1.0) to 84.0 Gbit/s (HDMI 2.2)
2. Calculate bits per pixel: Multiply the color depth (bits per component) by the number of components for the chosen color format — 3 for RGB and YCbCr 4:4:4, 2 for YCbCr 4:2:2, 1.5 for YCbCr 4:2:0
3. Compute total pixels per frame: Add CVT-RBv2 blanking intervals (80 horizontal, 58 vertical) to the active resolution
4. Calculate maximum refresh rate: Divide the available data rate by the bits required per frame

$$\text{Max Hz} = \frac{\text{Data rate (from HDMI version spec)}}{(\text{Width} + 80) \times (\text{Height} + 58) \times \text{BPC} \times \text{Components}}$$

HDMI version comparison

Examples

4K 120 Hz with 8-bit RGB:

• Requires ~17.81 Gbit/s of data rate
• HDMI 2.0 (14.4 Gbit/s) is insufficient — HDMI 2.1 (42.0 Gbit/s) is needed
• This is why many 4K 120 Hz monitors and TVs require HDMI 2.1 ports

4K 60 Hz with 10-bit HDR (RGB):

• Requires ~11.14 Gbit/s
• HDMI 2.0 (14.4 Gbit/s) can handle it at 77% utilization
• HDMI 1.4 (8.16 Gbit/s) cannot — a common pain point for older HDR displays

8K 60 Hz:

• At 8 bpc RGB, requires ~71.24 Gbit/s
• Only HDMI 2.2 (84.0 Gbit/s) can drive this natively without compression

Options explained

• HDMI version — Determines the maximum available data rate. HDMI 1.0–2.0 use TMDS signaling with 3 channels; HDMI 2.1+ use FRL with 4 channels and more efficient encoding
• Resolution — Choose from common presets (720p through 8K, including ultrawide) or enter a custom resolution in pixels
• Color format — RGB and YCbCr 4:4:4 use full bandwidth; YCbCr 4:2:2 uses ~33% less; YCbCr 4:2:0 uses ~50% less. Note that YCbCr 4:2:0 is officially supported from HDMI 2.0 onward
• Color depth — Bits per color component: 8 bpc (standard), 10 bpc (HDR), 12 bpc (deep color), or 16 bpc. HDMI 1.0–1.2a supports deep color only with YCbCr 4:2:2; 16 bpc requires HDMI 1.3+

Features

• Covers all HDMI versions from 1.0 through 2.2 with specification-accurate data rates
• Calculates feasibility for six common refresh rates (60, 120, 144, 165, 240, 360 Hz) with bandwidth utilization percentages
• Supports custom resolutions and 10 built-in presets including ultrawide formats
• Accounts for CVT-RBv2 blanking overhead in all calculations
• Shows encoding scheme, data channels, and bits per pixel in the output

Use cases

• TV and monitor shopping: Verify whether your HDMI port version can drive a specific 4K or 8K display at the desired refresh rate before purchasing
• Gaming setup planning: Check if your console or GPU's HDMI version supports your target resolution and refresh rate, especially for 4K 120 Hz or 1440p 144 Hz gaming
• HDR content creation: Understand the bandwidth impact of switching from 8-bit to 10-bit or 12-bit color depth for professional video work