2:1 Aspect Ratio Calculator
2:1 double-wide — banners, headers and the Univisium cinema proposal.
2:1 (18:9) is the clean double-wide. X/Twitter header (~1500×500), Facebook cover and many site hero banners are effectively 2:1 or very close. It is also the Univisium framing proposal — a compromise between 1.33 and 2.39. Width is exactly twice height, so mental math is trivial but off-by-a-few-pixels headers still crop faces.
1920 × 960
Exact ratio: 2:1 · CSS: aspect-ratio: 2 / 1 · padding-top fallback: 50.00%
Formula
height = width × 1 ÷ 2
width = height × 2 ÷ 1
// padding-top fallback: 50.00% — keeps layout stable before the image loads
aspect-ratio: 2 / 1 — modern replacement for the padding hack
All math runs locally in your browser. No upload. Type either side, the other solves live — and the URL updates so you can share an exact pair (?w=1920&rw=2&rh=1) or bookmark a preset.
Common 2:1 resolutions
| Width | Height | Use |
|---|---|---|
| 320px | 160px | |
| 640px | 320px | |
| 1280px | 640px | |
| 1920px | 960px | |
| 2560px | 1280px | |
| 3840px | 1920px | 4K |
| 5120px | 2560px | |
| 7680px | 3840px |
Exact known sizes in this ratio
- 2160×1080 — 2160×1080 18:9 Phone (Tall phone displays (2:1))
When to use 2:1
- X/Twitter header & Facebook cover
- Website hero banners (2:1)
- Univisium / 18:9 phone displays
Pitfalls to avoid
- X header safe area is smaller than 1500×500 — keep text centered 1260×330 or so
- Rounded corners on social headers clip edges
CSS snippet
Modern:
.frame { aspect-ratio: 2 / 1; width: 100%; overflow: hidden; }
.frame > img { width: 100%; height: 100%; object-fit: cover; }Legacy padding hack (for very old browsers):
.wrap { position: relative; width: 100%; padding-top: 50.00%; }
.wrap > * { position: absolute; inset: 0; }Pair with object-fit: contain to letterbox without cropping, or cover to fill and crop safely.
Platform reference
Frequently asked
What size is a 2:1 banner at 1200 wide?
1200×600 — height is exactly half the width.
Is 2:1 the same as 18:9?
Yes. Multiply 2:1 by 9 → 18:9. Same ratio, different notation.
What is Univisium?
Cinematographer Vittorio Storaro’s proposal that all content be framed at 2:1 as a universal compromise.
Tip: add ?w=1920 or ?h=1080 to this URL to prefill the calculator — useful for linking from a spec doc.
Other ratios
- 16:9 Aspect Ratio Calculator
- 4:3 Aspect Ratio Calculator
- 1:1 Square Calculator
- 9:16 Vertical Calculator
- 21:9 Ultrawide Calculator
- 3:2 Aspect Ratio Calculator
- 16:10 Aspect Ratio Calculator
- 4:5 Portrait Calculator
Look up by resolution
- 1920×1080 — 1920×1080 Full HD
- 1280×720 — 1280×720 HD
- 3840×2160 — 3840×2160 4K UHD
- 2560×1440 — 2560×1440 QHD
- 1366×768 — 1366×768 WXGA
- 3440×1440 — 3440×1440 UW-QHD
What aspect ratio is 1920×1080? → · Full FAQ →