There is no length limit in the HDMI standard, but metal cables are typically up to 15m.
Most cables on the market have a length of up to 15m.
When looking, they are probably sold up to about 20m high.
However, there are different types of extenders on the market that can be used to extend lengths beyond 100m.
Below is an extender that uses coaxial cable and allows extension up to 120m.
