NVR Storage Size Chart

How to Use This Chart

Pick the table for how you’ll record — Continuous (24/7) or Motion-Only (about 8 hours a day) — then find your resolution down the left and your camera count and retention across the top. The cell is the approximate total terabytes for that setup on H.265. Round up: if the chart says 5.2 TB, buy a 6 TB or 8 TB surveillance drive so you’re not running at the edge.

The chart is built for a fast, no-input answer. If your frame rate isn’t the typical 15 fps, your retention isn’t 14 or 30 days, or you’re mixing resolutions, the NVR Storage Calculator will give a closer number — this chart gets you in the right ballpark before you shop.

When This Tool Is Most Useful

This chart is most useful when you’re:

• Getting a fast storage ballpark without entering anything
• Comparing how resolution or camera count changes the drive size
• Sanity-checking a drive you already own against your plan
• Deciding between motion-only and continuous recording by seeing the gap
• Shopping for a surveillance drive and needing a target size

Worked Example

Say you’re planning eight 4MP cameras and want 30 days of footage. Read it two ways:

• Continuous (24/7): the 4MP row, 8 cams · 30 days column shows about 10.4 TB — that points to a 12 TB drive or a two-bay NVR.
• Motion-only: the same cell in the second table is about 3.5 TB — a 4 TB drive covers it. Recording on motion instead of 24/7 cuts the requirement by roughly two-thirds here.

Now see what resolution costs. Keep those eight cameras on motion for 30 days but step from 4MP up to 4K (8MP) and the figure roughly doubles to about 6.9 TB — a 4 TB drive no longer fits, so you’re into 8 TB. Drop instead to 1080p and it falls to about 1.7 TB. Same cameras, same retention: resolution alone moves the drive size by roughly 4×.

That’s the chart’s real lesson: recording mode and resolution swing storage far more than camera count. Before buying the biggest drive, decide whether you truly need 24/7 over motion, and whether every camera needs 4K or only the one watching the driveway. Then round up one size for headroom and choose a surveillance-rated drive built for constant writing. For a number matched to your exact frame rate and retention, run it through the calculator.

Common Mistakes

• Reading the wrong table. The continuous and motion-only numbers differ by three to four times — make sure you’re on the table that matches how you’ll actually record.
• Buying the exact figure. The chart is a floor. Round up a drive size for busy scenes and future cameras.
• Assuming camera count is the big lever. Resolution and recording mode move storage more; eight 1080p cameras can need less than four 4K ones.
• Using a desktop drive. These figures assume constant 24/7 writing; a desktop drive (WD Blue, Barracuda) isn’t built for it and fails early. Use WD Purple or Seagate SkyHawk.
• Forgetting frame rate. The chart assumes about 15 fps; a camera at 30 fps for plates uses roughly double its row.

Accuracy & Assumptions

The chart assumes typical H.265 bitrates (2/4/5/8 Mbps for 2/4/5/8MP), about 15 fps, and motion-only modeled at roughly 8 hours a day. Your real usage shifts with:

• Scene activity — a busy street or motion-heavy yard records more than the table; a quiet interior less
• Frame rate — 30 fps roughly doubles a row; lower fps reduces it
• Codec — these are H.265 figures; older H.264 gear roughly doubles them
• Motion tuning — sensitivity and how much really moves change the motion-only totals a lot
• Audio and sub-streams — extras add a little on top

Treat the chart as a starting point, size up, and confirm with the calculator or your NVR’s own estimate.

Next Steps

Want a figure tuned to your exact frame rate and retention? Use the NVR Storage Calculator. Planning the network side too? The Camera Bitrate & Bandwidth Chart shows the throughput those cameras create. For the full reasoning — codecs, drives, and retention trade-offs — read how much NVR storage you need, and if your NVR won’t accept a drive, see the “no hard disk” fix.

Related Resources

Related calculators & charts

• NVR Storage Calculator — a figure tuned to your exact setup
• Camera Bitrate & Bandwidth Chart — the data rate behind the storage
• PoE Budget Calculator — power the cameras you’re sizing storage for

Related guides

• How Much NVR Storage Do You Need? — the full sizing walkthrough
• NVR Says “No Hard Disk” or Won’t Record — get a new drive recognized

Browse all free security camera & NVR tools.

Frequently Asked Questions

How many TB do I need for 4 security cameras?

For four 4MP cameras recording continuously, roughly 2 to 4 TB covers about two weeks, depending on frame rate. Motion-only recording can cut that to 1 TB or less. Check the chart row for your resolution, or run your exact setup through the storage calculator for a precise figure.

How long will a 2TB drive record security footage?

A 2 TB drive holds roughly one to two weeks of continuous footage for a small 1080p to 4MP system, and considerably longer on motion-only recording. Higher resolution or more cameras shortens that quickly, which is why the chart breaks it out by both resolution and camera count.

Does higher resolution need more storage?

Yes, substantially. Each jump in resolution, from 1080p to 4MP to 8MP 4K, increases the data each camera produces, so storage needs climb fast. That is the single biggest factor in the chart, ahead of even camera count for many setups.

How much storage do 8 cameras need for 30 days?

On H.265, eight 4MP cameras recording continuously for 30 days need about 10.4 TB, or about 3.5 TB on motion-only. Eight 4K cameras roughly double that. Round up to the next surveillance drive size, so a 12 TB drive or a two-bay NVR for the continuous 4MP case.

Is motion-only recording worth it for storage?

Yes, for most homes. Motion-only recording uses roughly a third of continuous storage in these figures, because nothing is written when the scene is empty. Set a short pre-motion buffer so you catch the run-up to an event, and reserve continuous recording for high-traffic areas.

What size hard drive should I buy for my NVR?

Find your setup in the chart, then round up to the next drive size for headroom, so a 5.2 TB estimate means a 6 or 8 TB drive. Always choose a surveillance-rated model such as WD Purple or Seagate SkyHawk, built for continuous writing, over a desktop drive.

Why is my storage filling up faster than the chart says?

Usually a busier scene, a higher frame rate, or continuous instead of motion recording. The chart assumes typical H.265 bitrates at about 15 fps, so a motion-heavy view, 30 fps, or older H.264 gear can push usage well above the listed figure. Size up and recheck your camera bitrate settings.

Last updated: July 2026