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🌿 Landscape Lighting Calculator

Several fixtures on one cable, not one load at the end. See the voltage at every light, and how four wiring layouts compare.

V

Many transformers offer several taps — 12, 13, 14, 15 V — so you can lift the whole run to make up for the drop.

V

This is what the fixture is designed for, which is not the same as the tap you feed it from. It is what we use to work out the current.

Direct-burial landscape cable is almost always copper. 12 AWG is the common choice.

Distance along the path (ft) Load per fixture

Two fixtures at the same distance are treated as two lights on one tap. Rows can go in any order.

Rated amps is the firmest number. Watts is the weakest, because watts alone cannot tell us the current.

Leave this blank and we assume 1.0, which is a best case — the real current is higher, and so is the real drop.

Fill many fixtures at once

This only fills the rows below. Correct any of them afterwards.

Check against your fixture's limits

We do not invent a voltage limit. Enter the window from your fixture's data sheet and every tap gets checked against it.

Why one cable with several lights is different

Every other calculator here, including ours, assumes one load at the far end of one run. A landscape run taps fixtures along the cable, so the stretch nearest the transformer carries all of them and the last stretch carries one. The true drop is the sum of the stretches, which is far less than pretending the whole load sits at the end. This tool works it out stretch by stretch.

The four layouts in plain English

A daisy chain runs one cable and taps each fixture in turn — least cable, biggest difference between first and last. A T split runs one trunk to a dividing point and then two branches in opposite directions, so each branch carries about half the load. A star runs a separate cable from the transformer to every fixture — most cable, best worst-case voltage. A hub runs one trunk out to a junction point and then a short spoke to each fixture. There is no single winner, which is why all four are shown.

What this tool does not do

This answers voltage drop only. It does not check that your cable is rated to carry the current, it does not check your transformer's capacity, and it does not evaluate CEC compliance or your fixture manufacturer's requirements. Use the Canadian ampacity check for the current-carrying question, and your fixture's data sheet for the voltage window.