The flag of Niue consists of two parts: a yellow field and the Union Jack in the canton (upper hoist-side quadrant). The Union Jack has a blue field with red crosses and white borders. In the center of the yellow field, there is a white star with five points.

Color codes:

• Yellow: Pantone 116 C, HEX #FFCD00
• Blue (Union Jack): Pantone 280 C, HEX #012169
• Red (Union Jack): Pantone 186 C, HEX #C8102E
• White: HEX #FFFFFF

The aspect ratio of the flag is 1:2, meaning its width is twice its height. Exact measurements depend on the size of the flag being produced, but the proportions remain constant. The Union Jack canton occupies one quarter of the flag, with dimensions equal to half the height and width of the entire flag. The white star's diameter is equal to one-twelfth of the flag's width.

Geometric properties:

• The Union Jack consists of three crosses: St George's Cross (red on white), St Andrew's Cross (white diagonal on blue), and St Patrick's Cross (red diagonal on white).
• The white star is a regular pentagon with equal sides and angles, placed at the center of the yellow field.