How Long a Starlink Cable Do You Need?

The three numbers are the height of the mount position above ground, the horizontal distance from there to where the cable will enter the building, and the distance inside from the entry point to wherever the router will sit.

People consistently underestimate the third one. The cable does not travel in a straight line through a building — it follows joists, drops down cavities, and goes around obstacles. If the router is in a basement on the other side of the house from the entry point, that interior run can easily be longer than everything outside it.

The estimate adds roughly three metres for slack. That covers the drip loop below the entry point, a service loop at each end so the cable is not under tension, and the reality that a cable run is never as direct as a tape measure suggests. Round up rather than down.

Once your figure exceeds the longest cable Starlink offers, the answer is a different design rather than a longer cable. Put the router close to the dish — in a shop, an outbuilding, or a weatherproof enclosure — and distribute the network from there over standard Ethernet, which gives you a hundred metres per hop and can be repeated with a switch.

Where even that is impractical, a directional point-to-point wireless link between buildings covers distances cable cannot reach economically. Both approaches remove the constraint entirely, and both need deciding before the dish goes up rather than after.