HDMI TMDS Clock Calculator
Compute HDMI TMDS (Transition-Minimized Differential Signaling) clock and data rates for common resolutions and HDMI versions.
How to Use
- Enter video resolution, frame rate, and color depth (8/10/12 bit).
- Tool computes TMDS clock, total data rate, and required HDMI version.
Show Work
Formulas
History of HDMI
HDMI 1.0 (December 2002) defined TMDS signaling at 165 MHz - sufficient for 1080p60 8-bit color. Each subsequent version raised the maximum pixel clock: 1.3 (2006) to 340 MHz for deep color, 2.0 (2013) to 600 MHz for 4K60, 2.1 (2017) abandoned the TMDS clock lane and switched to 48 Gbps FRL (Fixed Rate Link) to support 8K60 and 4K120. The original TMDS encoding from Silicon Image uses an 8b/10b mapping designed to minimize transitions and maintain DC balance over inexpensive passive cables.
About This Calculator
Pick resolution, frame rate, and color depth. The tool computes pixel clock (active pixels + 25% blanking overhead), TMDS clock (scales with color depth), total data rate across the 3 RGB lanes, and minimum required HDMI version.
For HDMI 2.1 Fixed-Rate Link at 8K/120 Hz, the encoding changes to 16b/18b with embedded clock. For display simulation, many video test patterns can be generated by FPGAs (Xilinx, Lattice) with integrated HDMI transmitter PHYs. Everything runs client-side.
About the HDMI TMDS Clock Calculator
Use the HDMI TMDS Clock Calculator — a free, easy tool for electronics and circuit design. Nothing is uploaded, and you do not need an account. Compute HDMI TMDS (Transition-Minimized Differential Signaling) clock and data rates for common resolutions and HDMI versions.
How it works
Put each value in its box and read the answer as you go. Because it recalculates live, you can play with the inputs to see how each one moves the result — handy for checking your own working or planning ahead. Everything happens on your device, so it is fast and private.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
What is TMDS?
Transition-Minimized Differential Signaling — HDMI\'s physical layer. Each color channel (R, G, B) is 8 bits, encoded to 10 bits for DC balance + transition minimization. One TMDS clock = one pixel.
HDMI versions?
HDMI 1.4: max 340 MHz TMDS (1080p60 10-bit HDR). HDMI 2.0: 600 MHz (4K60 8-bit). HDMI 2.1: 12 Gbps per lane (4K120, 8K60).
Lane count?
HDMI 1.x/2.0: 3 TMDS data lanes + 1 clock lane. HDMI 2.1 FRL (Fixed Rate Link): 3 or 4 data lanes, no separate clock (embedded).
How do I use the HDMI TMDS Clock Calculator?
Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.
Do I need to install or sign up for anything?
Not at all — it runs in the browser with nothing to install and no account. After it loads once, it even works without an internet connection.
Is my information private?
Yes. Everything happens in your browser. Nothing you type is sent to a server or saved anywhere.
Common Use Cases
1080p60 8-bit
148.5 MHz TMDS — HDMI 1.3+. Baseline HDTV.
4K60 10-bit HDR
594 MHz TMDS — needs HDMI 2.0 Premium High-Speed cable.
8K60 12-bit
HDMI 2.1 FRL at 48 Gbps; requires Ultra High-Speed cable.
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