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RatioCalc

What aspect ratio is 1080×1350?

4:5 (~0.8000:1)

1080×1350 simplifies to 4:5 (GCD 270). In decimal that is ~0.8000:1 — a standard 4:5 frame used for instagram portrait feed. The calculator below is preloaded to 4:5 so you can solve any partner dimension at the same ratio.

→ Open the full 4:5 Portrait Calculator →

:

1920 × 2400

Exact ratio: 4:5 · CSS: aspect-ratio: 4 / 5 · padding-top fallback: 125.00%

How the ratio was computed

GCD(1080, 1350) = 270

1080 ÷ 270 = 4 → 1350 ÷ 270 = 5

→ 4:5 (dec. 0.8000:1) · padding-top 125.00%

CSS: aspect-ratio: 4 / 5

All math is local and instantly invertible — swap width and height and the ratio stays the same, just rotated. URL sharing works: ?w=1080&h=1350 style deep-links still resolve via the ratio parameters.

Quick 4:5 partner table

WidthHeight (4:5)
640px800px
1280px1600px
1920px2400px
2560px3200px
3840px4800px

Other sizes in 4:5

No other catalogued sizes share 4:5 exactly — the table above covers the common computed variants.

Related lookups

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Tip: designing for 1080×1350 portrait 4:5? Master at 1080×1350 exactly, then export lighter proxies by halving both sides (e.g. 540×675) — the ratio stays 4:5 and downscales stay sharp.