How to Work Out How Many Downlights You Need

There are two things to balance: how bright the room needs to be, and how evenly the light is spread. Our calculator handles both, but here is the logic behind it so you can sanity check the result.

1. Start with brightness (lumens per square metre)

Different rooms need different light levels. As a guide for Australian homes:

• Living rooms and bedrooms: around 100 to 150 lumens per m² for a relaxed, ambient feel.
• Kitchens and bathrooms: around 300 to 400 lumens per m² because they are task areas.
• Hallways, studies and stairs: somewhere in between, around 150 to 250 lumens per m².

Multiply your room area by the target figure to get the total lumens you need, then divide by the output of one downlight. Most quality 10W LED downlights produce roughly 900 to 1400 lumens.

2. Then space them evenly

Once you know the quantity, spread them out so the light is even:

• Space downlights roughly 1.2m to 1.5m apart, centre to centre.
• Keep the outer downlights about 600mm off the walls.
• Line them up in a regular grid so there are no dark patches.

Quick Examples

• 4m x 4m living room (16m²): about 6 to 9 downlights at 3000K warm white.
• 3m x 4m kitchen (12m²): about 8 to 10 downlights at 4000K cool white for bench lighting.
• 2m x 3m bathroom (6m²): about 4 downlights, IP44 rated, 4000K.
• 1m x 4m hallway (4m²): 2 to 4 downlights evenly spaced.

Tips for Getting the Layout Right

• Match colour temperature to the room: 3000K warm white for living and bedrooms, 4000K cool white for kitchens and bathrooms. Tri-colour downlights let you switch on the fitting.
• Mind wet areas: bathrooms need IP44 minimum, and IP54 or IP65 near the shower.
• Insulation: if your ceiling has insulation batts, choose IC-F rated downlights so insulation can sit against the fitting safely.
• Dimming: pair dimmable downlights with a compatible LED dimmer for full control.
• Installation: in Australia, downlights must be installed by a licensed electrician. Plan positions before plastering if you are building or renovating.

Downlight Calculator FAQs

How many downlights do I need per square metre?

For ambient living spaces aim for around 100 to 150 lumens per m², and for kitchens and bathrooms aim for 300 to 400 lumens per m². Divide the total lumens by the output of one downlight to get the quantity.

How far apart should downlights be?

Space them roughly 1.2m to 1.5m apart, centre to centre, and keep the outer ones about 600mm off the walls for even coverage.

How many downlights in a kitchen?

A typical 12m² kitchen needs around 8 to 10 downlights at 4000K cool white, depending on ceiling height and bench layout. Use the calculator above for your exact size.

Can I install downlights myself?

In Australia you must use a licensed electrician to install or hardwire a 240V downlight. You can legally replace a GU10 globe yourself.