Spain

What the source says

Checked against the constituting document

La bandera de España está formada por tres franjas horizontales, roja, amarilla y roja, siendo la amarilla de doble anchura que cada una de las rojas.

[1] Constitución Española, Artículo 4.1 (Agencia Estatal Boletín Oficial del Estado), read on 2026-07-17. Backs which colors the flag has and the description of the design on this page.

Checked means compared against the quoted text, not read by a person. What the marks mean.

Colors and meaning

Red[1] #AA151B
Historically drawn from the royal banner of the Crown of Castile and Aragon
Yellow[1] #F1BF00
The same historic royal heraldic tradition

What the law specifies[1]

The constitution defines the flag as three horizontal stripes — red, yellow, red — with the yellow stripe twice the width of each red one. That is the whole of the constitutional description: it sets no overall ratio, assigns the colours no meaning, and does not mention the coat of arms, which is governed separately.

Symbolism and history

A wide yellow band between narrower red bands carries the national coat of arms offset toward the hoist, a design dating to 1785 when King Charles III sought a flag more visible at sea than Spain's previous plain red-and-white naval ensigns.

Most similar flags

The 6 closest of the 194 other national flags, ranked by a similarity index computed from the flag images themselves. The number is that index, 0–100 — not a claim that the two flags are “X% identical”.

Computed at build time: each flag is rasterised to 64x48, and the score is 0.55 × colour overlap + 0.45 × structure. A different weighting would rank these differently. How the index works.

Sources

[1] Verified against Constitución Española, Artículo 4.1 (Agencia Estatal Boletín Oficial del Estado) on 2026-07-17. Backs which colors the flag has and the description of the design on this page. The passage it was checked against is quoted at the top of this entry.

Further reading: Flag of Spain on Wikipedia