What do the colours of the Australia flag mean?

Blue: the field, inherited from the British Blue Ensign. White: the stars. Red: present only within the Union Jack.

How do you tell the Australia flag from the New Zealand one?

New Zealand has four stars, not six, they are red with white borders rather than plain white, and there is no large Commonwealth Star.

When was the Australia flag adopted?

The current design dates from 1908, and its official ratio is 1:2.

The flag of Australia

A blue field with the Union Jack in the canton, a large white seven-pointed star beneath it, and the five stars of the Southern Cross in the fly.

Ratio 1:2 · current design adopted 1908

Australia

Field and colours only. Not shown: the Union Jack canton, the Commonwealth Star, and the Southern Cross.

The Commonwealth Star had six points when the flag was chosen in 1901 and gained its seventh in 1908 to cover the territories. The Southern Cross stars are not identical: four have seven points and the smallest, Epsilon Crucis, has five — a distinction Australia introduced in 1908 and New Zealand never adopted. The winning design came from a 1901 competition with five joint winners, including a fourteen-year-old schoolboy, who shared the prize money. Since 1995 the Aboriginal flag and the Torres Strait Islander flag have also been official flags of Australia, and the Commonwealth bought the Aboriginal flag's copyright outright in 2022.

Flags it gets confused with

Australia

Field and colours only. Not shown: the Union Jack canton, the Commonwealth Star, and the Southern Cross.

New Zealand

Field and colours only. Not shown: the Union Jack canton and four red stars of the Southern Cross.

Drawn at each flag’s own official ratio, which is itself the difference in some of these pairs.

Flag	How to tell them apart
New Zealand	New Zealand has four stars, not six, they are red with white borders rather than plain white, and there is no large Commonwealth Star.

What the colours mean

Flag laws usually specify a Pantone chip, a CMYK mix or just a colour name. Converting any of those to sRGB is lossy, which is why published hex values disagree.

The symbols on it

What	What it stands for
Commonwealth Star	Seven points: six for the original states, one for the territories
Southern Cross	The constellation Crux, visible year-round across Australia

Ratio: 1:2
Current design adopted: 1908
Colours: blue, white, red

Common questions

What does the flag of Australia look like?: A blue field with the Union Jack in the canton, a large white seven-pointed star beneath it, and the five stars of the Southern Cross in the fly.
What do the colours of the Australia flag mean?: Blue: the field, inherited from the British Blue Ensign. White: the stars. Red: present only within the Union Jack.
How do you tell the Australia flag from the New Zealand one?: New Zealand has four stars, not six, they are red with white borders rather than plain white, and there is no large Commonwealth Star.
When was the Australia flag adopted?: The current design dates from 1908, and its official ratio is 1:2.

Australia Capital, area, population and currency
The flag of New Zealand Routinely mistaken for this one
Every flag with blue in it
The flag of United States Ratio 10:19
The flag of India Ratio 2:3
The flag of United Kingdom Ratio 1:2
The flag of France Ratio 2:3
The flag of Russia Ratio 2:3
The flag of Brazil Ratio 7:10
The flag of South Korea Ratio 2:3
The flag of Ukraine Ratio 2:3

Sources

Official vendor product documentation — At One Place

How these figures are compiled and checked