Free Tool
Aspect Ratio Calculator
Resize any video while keeping its ratio, and grab the exact pixel size for every platform — TikTok, Reels, Shorts, Instagram, YouTube and X. Free, in your browser.
Original size
×
Aspect ratio: 16:9
New size (keeps ratio)
×
Type one dimension — the other is filled to match the ratio.
Common social video sizes
| TikTok / Reels / Shorts | 9:16 | 1080 × 1920 |
| Instagram feed (portrait) | 4:5 | 1080 × 1350 |
| Instagram / square | 1:1 | 1080 × 1080 |
| YouTube (landscape) | 16:9 | 1920 × 1080 |
| X / Twitter (landscape) | 16:9 | 1280 × 720 |
| YouTube thumbnail | 16:9 | 1280 × 720 |
Tap a row to load it above. All calculated in your browser.
Need the vertical clips too?
MomentClip turns a long video into ready-to-post 9:16 clips for TikTok, Reels and Shorts — free to try, no signup, no watermark.
Clip a video freeFrequently asked questions
How do I calculate a new size keeping the aspect ratio?+
Enter your original width and height, then type one new dimension. The tool fills in the other so the ratio stays identical — no stretching or black bars.
What aspect ratio is TikTok, Reels and Shorts?+
All three use 9:16 vertical, ideally 1080×1920 pixels. Instagram's feed also supports 4:5 (1080×1350) and square 1:1 (1080×1080).
What size should a YouTube video be?+
16:9 landscape, 1920×1080 (Full HD) is standard. YouTube thumbnails are also 16:9, at 1280×720.
Does this upload my video?+
No — it's a pure calculator that runs in your browser. Nothing is uploaded.
More free tools
100% in‑browser · no upload · no signup