Every Other Country on Earth Flies a Rectangle. Nepal's Flag Is Built From Math Instead.
Nepal is the only nation whose flag isn't a quadrilateral — and its exact shape isn't a designer's choice, it's a formula written into the constitution.

At a glance
- Published
- TopicRecords & People
- Verified againstEncyclopaedia Britannica
- Treks coveredKathmandu Valley Cultural Tour — 3 Days, Nepal Classic Tour — 7 Days
Pick any of the world's other flags and you're looking at a rectangle. Stripes, crosses, cantons, stars — the shape underneath is always the same four-sided frame. Nepal is the single exception. Its flag is two stacked triangular pennants, crimson with a blue border, and the reason it still looks that way has nothing to do with taste. It's geometry, fixed by law.
Key facts
- Nepal flies the only national flag on Earth that isn't a rectangle — every other sovereign nation's flag is some form of quadrilateral.
- It is built from two stacked triangular pennants, crimson with a blue border.
- Its current form was fixed by Nepal's constitution on 16 December 1962, geometry included.
- The upper pennant carries a moon with 8 rays; the lower carries a sun with 12 rays.
The two pennants aren't a modern graphic-design flourish. For roughly two centuries they were separate banners flown by rival branches of Nepal's ruling dynasties — one for the Shah kings, one for the Rana family that held the office of prime minister. Nepal's mountain kingdoms and principalities used pennant-shaped banners long before the rectangular flag became the global default. When the rest of the world standardised on rectangles — a trend set largely by European navies and colonial administrations — Nepal had no colonial ruler to impose the convention. The two dynastic pennants were eventually stacked into one flag, and that double-pennant shape simply never got swapped out.
The shape is a formula, not a sketch
What sets Nepal's flag apart from almost every other national symbol is that its geometry is legally exact, not approximate. The constitution specifies the construction the way a geometry textbook would: the flag's overall height is fixed at exactly 4/3 of its width, the baseline of the triangle equals the flag's width, and the triangle's height is exactly 3/4 of the flag's height. A sign-painter or a satellite manufacturer can reconstruct the flag from those ratios alone, with a compass and straightedge, without ever having seen a picture of it.
| Element | Specification |
|---|---|
| Overall shape | Two stacked triangular pennants |
| Height : width ratio | Exactly 4 / 3 |
| Triangle base | Equal to the flag's width |
| Triangle height | 3/4 of the flag's total height |
| Field colour | Crimson (the rhododendron, Nepal's national flower) |
| Border colour | Blue (peace) |
The sun and moon aren't decorative either. Early versions of both emblems had human faces worked into them; the 1962 standardisation simplified them into the clean geometric shapes flown today. Nepalis have long read the pairing as an expression of hope that the nation will last as long as the sun and the moon do — and, more literally, as a nod to the two dynasties whose pennants the flag is built from.
The Shah and Rana dynasties each fly their own triangular banner across the hill kingdoms of Nepal.
The two pennants are combined into a single double-pennant flag as Nepal unifies.
Nepal's new constitution locks the flag's exact geometry — height, width, triangle ratios — into statute.
195-odd flags later, Nepal remains the sole holdout from the rectangle.
What this means for travellers
What this means for you
You'll see this flag everywhere the moment you land — strung across Kathmandu's Durbar Square, painted on trekking lodges, clipped to a guide's backpack at Everest Base Camp. It's one of the few national symbols you can actually reconstruct with a ruler, and locals take real pride in explaining why. If you want the full story in person — the temples, the old royal squares, the living history behind those two pennants — our Kathmandu Valley Cultural Tour and Nepal Classic Tour both spend real time in the plazas where this flag has flown for generations.
Source: Encyclopaedia Britannica, "Flag of Nepal".
Cover photo: CAPTAIN MEDUSA via Wikimedia Commons (CC BY-SA 4.0).
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