HD laptop 1366×768 vs 15.6″ / 17″ Full HD @ 125%: screen size for websites
The 15.6″ / 17″ Full HD @ 125% is 170px wider and 96px taller in CSS pixels. That’s enough for a layout that fits the 15.6″ / 17″ Full HD @ 125% to spill on the HD laptop 1366×768.
| HD laptop 1366×768 | 15.6″ / 17″ Full HD @ 125% | |
|---|---|---|
| CSS viewport | 1366 × 768 | 1536 × 864 |
| Visible on first load | 1366 × 633 (Chrome (Windows 11)) | 1536 × 729 (Chrome (Windows 11)) |
| Device pixel ratio | 1 | 1.25 |
| Physical resolution | 1366 × 768 | 1920 × 1080 |
| Screen size | 15.6″ | 15.6″ |
| Aspect ratio | 16:9 | 16:9 |
| Tailwind breakpoint | xl | 2xl |
| Bootstrap tier | xl | xxl |
| Full-width image needs | 1366px | 1920px |
| Released | – | – |
See your site on both, side by side
Paste your address (or localhost:3000). doesitfit shows it on the HD laptop 1366×768 and 15.6″ / 17″ Full HD @ 125% at their exact sizes, next to each other.
Free, no sign-up. Or ask Claude, ChatGPT or Codex to check it.
What the difference means for your site
Width: 1366px vs 1536px
Headings and buttons wrap differently: a line that fits in 1536px can break onto two lines in 1366px. Anything with a fixed width between the two makes the narrower screen scroll sideways (fix it).
Height: 768px vs 864px
On first load a page shows 633px on the HD laptop 1366×768 and 729px on the 15.6″ / 17″ Full HD @ 125%, so “above the fold” differs by 96px.
Questions people ask
Is the HD laptop 1366×768 screen bigger than the 15.6″ / 17″ Full HD @ 125% for websites?
The 15.6″ / 17″ Full HD @ 125% is 170px wider and 96px taller in CSS pixels. That’s enough for a layout that fits the 15.6″ / 17″ Full HD @ 125% to spill on the HD laptop 1366×768.
What are the viewport sizes of the HD laptop 1366×768 and 15.6″ / 17″ Full HD @ 125%?
HD laptop 1366×768: 1366 × 768 CSS px (DPR 1). 15.6″ / 17″ Full HD @ 125%: 1536 × 864 CSS px (DPR 1.25).
Do I need to test my site on both?
Yes if your layout has anything close to 1536px wide. Test the narrower one first: it’s where things spill.
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