NVR Storage Calculator

NVR Storage Calculator helps you estimate hard drive needs before buying or upgrading storage. Camera count, recording hours, video quality, and retention days all affect the final drive size. Use this tool to turn those settings into a clear storage estimate, check whether the original drive is enough, and see how many drives or devices your setup may require.

Results are estimates only. Actual storage use may vary based on scene complexity, motion frequency, lighting, resolution, frame rate, compression, recording mode, firmware behavior, and specific device settings over time.

Table of contents:

• What Is the NVR Storage Calculator?
• How Do You Use the NVR Storage Calculator?
• How Is NVR Storage Calculated?
• How Do H.265 and H.264 Affect Storage?
• How Should You Read the Calculator Results?
• FAQs

What Is the NVR Storage Calculator?

An NVR storage calculator turns camera settings into a practical storage plan. Enter camera count, recording mode, recording time, and retention days, and the tool estimates hard drive capacity and drive or device count.

You can use three modes:

• eufy PoE NVR Security System S4 is for wired systems that record continuously.
• eufy HomeBase™ S380 (HomeBase™ 3) is for wireless battery cameras that usually save event clips.
• Generic NVR works for any brand when you want to enter your own drive size and camera settings.

How Do You Use the NVR Storage Calculator?

Use the inputs as a checklist. Each one changes the final drive size.

The output shows total TB, recommended drive size, drive or device count, and whether the original drive is likely to meet your plan.

How Is NVR Storage Calculated?

The calculator follows the same flow every time.

1. It estimates one camera's hourly video size:

• Formula: Per-camera hourly storage in GB = bit rate in Mbps x 3600 ÷ 8 ÷ 1024

1. It calculates total recording time:

• Formula: Continuous recording hours = camera count x daily hours x retention days
  Event recording hours = camera count x daily events x clip seconds ÷ 3600 x retention days

1. It turns that into required storage:

• Formula: Required storage in TB = per-camera hourly GB x total hours ÷ 1024

In plain language, the calculator multiplies one camera's hourly video size by camera count and recording time. If 4 cameras record all day for 30 days, it counts 4 x 24 x 30 hours, then applies the bit rate.

Here are decision-style examples using the same formula. Recommended drive size includes usable-capacity conversion and a 90% drive-fill target. Generic count assumes 4 TB drives.

The tool also accounts for real usable capacity. A drive sold as 4 TB may not show as a full 4 TB because capacity is counted differently.

In formula form, usable capacity = labeled TB x 0.9095.

The calculator also aims for no more than 90% drive fill.

Suggested drive size is based on required storage ÷ 0.9, leaving room before the drive gets too full.

How Do H.265 and H.264 Affect Storage?

The codec you choose affects storage cost. At similar image quality, H.264 files are about twice the size of H.265 files, so H.265 can roughly halve the space your footage needs. That may mean more recording days on the same drive, or a smaller and cheaper one.

This is why the calculator treats the default H.264 bit rate as the default H.265 bit rate x 2, and it already knows the default codec for common eufy cameras.

You can switch the codec manually and watch the estimate update before you buy a drive.

How Should You Read the Calculator Results?

The total TB number is estimated video size. Recommended drive size is the planning number because it includes usable-capacity adjustment and the 90% fill buffer.

For eufy NVR S4 and HomeBase 3 modes, the tool checks standard drive sizes such as 1, 2, 4, 8, and 16 TB, then picks the smallest size that covers the estimate. Common eufy NVR S4 configurations include a 2 TB HDD and support upgrades up to 16 TB. In Generic mode, you enter your own drive size, and the calculator estimates how many drives are needed.

FAQs

How much storage do 4 cameras need for 30 days?

It depends on resolution, bit rate, codec, and recording mode. For example, 4 cameras recording continuously at 4 Mbps for 30 days need about 4.9 TB before a planning buffer.

What is the difference between continuous and motion or event recording?

Continuous recording saves video for the hours you choose each day. Event recording saves shorter clips when activity happens. Busy areas can still create many clips.

Can I upgrade the hard drive later?

In supported eufy NVR S4 setups, the drive can be upgraded up to 16 TB. Check your model before buying a replacement drive.

What does Generic mode do?

Generic mode is for non-eufy or mixed systems. You enter the main settings and your drive size, then the calculator estimates storage and drive count.

How long will a 2 TB NVR record?

A 2 TB drive can last very different lengths of time. A few event-based cameras may keep footage much longer than several cameras recording continuously.

Is an HDD or SSD better for an NVR?

Many NVR systems use HDDs because they offer large capacity at a lower cost per TB. SSDs can be fast and quiet, but compatibility and write workload still matter.

How many GB does 24 hours of CCTV recording use?

Use this rule: hourly GB = Mbps x 3600 / 8 / 1024. At 4 Mbps, one camera records about 42 GB per day before system-level adjustments.