How much data your streaming uses, and whether it fits your plan
Updated October 2026
| Quality (Netflix setting) | Per hour, per device | 2 hours a day for 30 days |
|---|---|---|
| Low (basic quality) | Up to 0.3 GB | 18 GB |
| Medium (standard quality) | Up to 0.7 GB | 42 GB |
| High, standard definition | Up to 1 GB | 60 GB |
| High, HD | Up to 3 GB | 180 GB |
| High, 4K Ultra HD | Up to 7 GB | 420 GB |
These are Netflix’s published maximums per device. On phones, Netflix’s Automatic setting gives about 4 hours per GB, Save Data about 6, and Maximum Data can use 1 GB every 20 minutes or more. YouTube’s help pages describe its quality settings (Auto, Higher picture quality, Data saver) without publishing GB-per-hour figures, so treat the Netflix numbers as a ceiling for comparable resolutions elsewhere.
Enter your household’s combined daily hours at each quality, counting each TV or device separately, then phone viewing on mobile data, the days in the month and your plan’s cap. Monthly GB = (low hours × 0.3 + SD hours × 1 + HD hours × 3 + 4K hours × 7) × days + phone hours ÷ 4 × days. For the default: (4 × 3 + 1 × 7) × 30 = 570 GB at home, plus 1 ÷ 4 × 30 = 7.5 GB on the phone, 577.5 GB in total. That is 48.1% of 1,200 GB, which leaves room for about 6.9 more hours of HD a day.
| Viewing | GB per month | Share of a 1,200 GB cap | Overage at $10 per 50 GB |
|---|---|---|---|
| Light: 2 h of HD a day | 180.0 | 15.0% | None |
| Default household: 4 h HD + 1 h 4K + 1 h phone | 577.5 | 48.1% | None |
| Phone only: 2 h a day on Automatic | 15.0 | 1.2% | None |
| Saver: 4 h a day in standard definition | 120.0 | 10.0% | None |
| 4K family: two TVs, 3 h of 4K each, plus 2 h HD | 1,440.0 | 120.0% | $50 |
Only the 4K family goes over. Overage is figured with Xfinity’s published rule for legacy plans with a 1.2 TB limit ($10 for each additional 50 GB, at most $100 a month, with the first overage in 12 months waived); new Xfinity plans include unlimited data, and other providers set their own terms.
A data cap counts everything on the connection: streaming, game downloads, video calls, cloud backups and software updates. As of August 2026, Xfinity applies its 1.2 TB limit only to older plans and not in a list of Northeastern states and Washington, D.C. Check your provider’s usage meter for the real figure; this calculator estimates streaming alone.
Counting the household once. Two TVs streaming at the same time use twice the data; add the hours for each device.
Assuming a 4K TV means 4K data. You only pay 4K data rates when the plan, app setting and title are all 4K. Many shows stream in HD.
Forgetting autoplay. Episodes that keep playing to an empty room count the same as watched ones.
Using maximums as averages. Netflix’s figures are “up to” values, so real use is often lower; the calculator gives a cautious upper estimate.