what is the largest downlight size in australia

The largest common downlight cutout size in Australia is usually around 90 mm to 95 mm , with 90 mm now the most standard size for modern LED downlights. Some older or oversized fittings can go larger, but they’re less common and usually special-case products.

Quick Scoop

In practice, if you’re buying or replacing a downlight in Australia, 90 mm is the size most people mean. A few suppliers still list larger shade diameters or larger legacy cutouts, but the market has largely standardized around 90 mm for ceiling holes.

What this means

• 90 mm cutout : the current “standard” for many homes and new LED fittings.

• 70 mm / 75 mm : still common in some products and older installs.

• Larger than 90 mm : exists, but usually for older ceilings, special designs, or retrofit situations.

Practical tip

If you’re measuring an existing hole, measure the ceiling cutout , not the visible trim size. The visible outer ring can be much larger than the actual hole size, and that’s what determines whether a replacement fits.

Bottom line

For Australia, the safest answer is: 90 mm is the main standard, and one of the largest widely used modern sizes; 95 mm and above are less common and usually non-standard.

TL;DR: Most Australian downlights are standardized at 90 mm cutout , with 70 mm also common and larger sizes available only in more limited cases.