In this article
After reading, you'll understand:
- What counts as HD, and how Full HD differs
- The resolutions inside the HD tier and their dimensions
- How HD compares to SD below and 4K above
- The bitrate and data HD actually needs
What is high definition?
HD, high definition, is video at 720p (1280×720) or higher. 720p is the entry point — the reason older TVs were sold as "HD ready" — and 1080p (1920×1080) is Full HD, the resolution most web video actually targets.
The label separates modern video from the standard-definition broadcast and DVD era below it. Above HD sits 4K (2160p), which some marketing calls Ultra HD.
HD in the resolution ladder
HD is a band, not a single number — it covers the two rungs most people watch on:
| Label | Resolution | Tier | Pixels |
|---|---|---|---|
| 480p | 854×480 | SD | 409,920 |
| 720p | 1280×720 | HD | 921,600 |
| 1080p | 1920×1080 | Full HD | 2,073,600 |
| 2160p | 3840×2160 | 4K / UHD | 8,294,400 |
720p and 1080p are both HD; 1080p is specifically "Full HD". Below is SD, above is 4K.
HD against SD and 4K
HD is the sweet spot: a clear step up from SD, without the bandwidth cost of 4K that most screens cannot show off anyway.
| Tier | Resolution | Pixels | Data per hour |
|---|---|---|---|
| SD | 480p | 409,920 | ≈450–900 MB |
| HD | 720p | 921,600 | ≈1.1–1.8 GB |
| Full HD | 1080p | 2,073,600 | ≈2.25–3.6 GB |
| 4K | 2160p | 8,294,400 | ≈9–16 GB |
The SD→HD jump is the one viewers notice; the HD→4K jump is visible only on large screens viewed close. For most course, webinar and sales video, Full HD is the right target.
What HD costs to deliver
With H.264, 720p needs roughly 2.5–4 Mbps and 1080p 5–8 Mbps — about 1.1–1.8 GB and 2.25–3.6 GB per hour respectively. A modern codec (H.265 or AV1) holds the same look at roughly half the bitrate.
You do not pick a single figure, though: adaptive bitrate encodes several HD renditions and the player switches between them as the connection changes.
How Kinescope handles this
Upload the best source you have — 1080p or 4K. Transcoding builds every HD rendition beneath it, and the adaptive player serves the largest one each viewer's connection carries over the CDN.
Read the Kinescope docsFrequently asked questions
What does HD mean in video?
HD stands for high definition — video at 720p (1280×720) or higher. 720p is the entry point and 1080p (1920×1080) is Full HD, the resolution most web video targets.
Is 1080p HD or Full HD?
Both. 1080p is HD, and specifically it is "Full HD" — the label used to distinguish 1920×1080 from the 720p sets once sold as merely "HD ready".
What is the difference between HD and SD?
HD starts at 720p; anything below, chiefly 480p, is SD (standard definition). HD carries at least 2.25 times the pixels and needs roughly double the bitrate, but it is the first tier where on-screen text stays sharp.
Is 720p considered HD?
Yes. 720p is the entry point to high definition — the reason older TVs were marketed as "HD ready", while 1080p sets were "Full HD".
What is the difference between HD and 4K?
4K (2160p) has four times the pixels of Full HD and needs three to four times the bitrate. The difference is clear on a large screen viewed close and largely invisible on a phone, which is why HD remains the right target for most video.
Do I have to choose HD myself?
No. Kinescope transcodes your upload into a full ladder and the adaptive player serves each viewer the largest HD rendition their connection supports — you upload one high-quality source.
Further reading
- High-definition video — Wikipedia — a vendor-neutral overview.
- SD (standard definition) — the tier below.
- 720p, 1080p and 4K — the numbers behind the labels.
