Deck Lighting Cost Calculator

Frequently asked questions

How many deck lights do I need?

Work from positions, not a total. One light per stair step or per riser, one per railing post if you want post caps, and one under-rail fixture every 6 ft of railing. A 16 by 12 ft deck with four steps and eight posts comes to about 19 fixtures for the usual package. Recessed floor lights, if you add them, go roughly one per 40 square feet.

What size transformer do I need for deck lighting?

Add up the wattage of every fixture and size the transformer so that total is about 80 percent of its rating. LED deck lights draw roughly one watt each, so 19 fixtures is around 23 watts — a 30 watt transformer covers it with a little spare. Leaving headroom matters because people almost always add lights later.

How much does deck lighting cost?

A DIY low-voltage package for a typical 16 by 12 ft deck with stairs and eight posts runs about $500 to $1,200 for fixtures, transformer and wire. Having an electrician install it adds roughly $600 to $1,300 on the same system. Recessed floor lights and integrated riser lights sit at the top of those ranges.

Can I add lighting to a deck that is already built?

Yes, but plan the routes first. Post caps and surface-mounted stair lights are straightforward because the wire runs along the underside of the rail or the stringer. Recessed floor lights and under-rail strips are much harder after the fact — the wire has to come up through the frame, which usually means working from below or lifting boards.