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RatioCalc

What aspect ratio is 900×1800?

1:2 (~0.5000:1)

900×1800 simplifies to 1:2 (GCD 900). In decimal that is ~0.5000:1 — a standard 1:2 frame used for pillar banner, vertical signage. The calculator below is preloaded to 1:2 so you can solve any partner dimension at the same ratio.

→ Open the full 1:2 Tall Portrait Calculator →

:

1920 × 3840

Exact ratio: 1:2 · CSS: aspect-ratio: 1 / 2 · padding-top fallback: 200.00%

How the ratio was computed

GCD(900, 1800) = 900

900 ÷ 900 = 1 → 1800 ÷ 900 = 2

→ 1:2 (dec. 0.5000:1) · padding-top 200.00%

CSS: aspect-ratio: 1 / 2

All math is local and instantly invertible — swap width and height and the ratio stays the same, just rotated. URL sharing works: ?w=900&h=1800 style deep-links still resolve via the ratio parameters.

Quick 1:2 partner table

WidthHeight (1:2)
640px1280px
1280px2560px
1920px3840px
2560px5120px
3840px7680px

Other sizes in 1:2

No other catalogued sizes share 1:2 exactly — the table above covers the common computed variants.

Related lookups

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Tip: designing for 900×1800 1:2 tall? Master at 900×1800 exactly, then export lighter proxies by halving both sides (e.g. 450×900) — the ratio stays 1:2 and downscales stay sharp.