Storage Calculator for CCTV Systems

June 17, 2026

Storage Calculator for CCTV Systems

Estimate CCTV camera storage from resolution, codec, frame rate, motion duty cycle, audio, retention target, RAID layout, hot spares, and disk reserve.

1 CCTV presets

2 Camera stream and retention inputs

TB matches drive labels; TiB is closer to what many operating systems display.

CCTV deployment type Adds a planning reserve for event clips, index files, and stream variation.

Number of CCTV cameras Count main streams that record to the NVR, DVR, NAS, or VMS.

Camera resolution class Resolution is converted to a practical baseline bitrate before codec and scene factors.

Compression codec profile Smart codecs help most in mostly static scenes with stable lighting.

Scene complexity and lighting Noise, rain, headlights, and trees can push real bitrate above clean daytime samples.

Recording frame rate factor The calculator uses 15 fps as the baseline for CCTV planning.

Bitrate source Use manual mode when your camera or VMS already reports main stream Mbps.

Manual main stream bitrate per camera (Mbps) Ignored unless manual bitrate mode is selected.

Recording schedule or trigger type Duty cycle changes storage, but the network still sees the full live stream.

Custom recording duty cycle (%) Used only when custom duty cycle is selected.

Audio bitrate per camera (Mbps) Audio is small per camera, but matters on large deployments.

Required retention period (days) Many home and small business systems aim for 14 to 45 days.

Storage layout for the recorder Parity protects against disk failure, but it also reduces usable camera storage.

Installed recorder drives Include installed bays, but not separate backup drives.

Drive label capacity each (TB) Use manufacturer decimal TB, such as 4, 8, 12, 16, 20, or 22 TB.

Hot spare drives Hot spares are installed but not counted as usable recording capacity.

Filesystem and recorder reserve (%) Leave free space for database indexes, filesystem behavior, and stable writes.

Incident export and bookmark space (%) Useful when evidence clips stay on the same recorder volume.

Bitrate growth and weather buffer (%) Adds headroom for firmware changes, night noise, added cameras, and higher quality.

Required CCTV storage

0 TB

target retention with buffers

Estimated retention

0 days

based on usable recorder space

Net usable capacity

0 TB

after RAID and reserve

Live ingest load

0 Mbps

main stream plus audio

Run the calculator to review the CCTV storage fit.

CCTV Storage Breakdown

3 CCTV equipment spec grid

1080p dome camera

Typical rate: 2 to 4 Mbps with H.264, lower with H.265.

Best use: doors, porches, indoor rooms, small offices.

Watch item: noisy night IR can double a clean daytime stream.

4 MP turret camera

Typical rate: 4 to 8 Mbps depending on motion and codec.

Best use: driveways, shop aisles, warehouse zones.

Watch item: wide scenes with trees and rain need buffer.

4K perimeter camera

Typical rate: 8 to 16 Mbps for useful forensic detail.

Best use: yards, parking edges, loading docks.

Watch item: substream previews do not reduce main recording.

LPR gate camera

Typical rate: 8 to 20 Mbps with high shutter settings.

Best use: gates, entrances, controlled lanes.

Watch item: continuous capture is common for plate evidence.

4 CCTV reference tables

Camera class	H.264 planning rate	H.265 planning rate	Good retention target
720p / 1 MP entry camera	1 to 2.5 Mbps	0.7 to 1.8 Mbps	14 to 30 days
1080p / 2 MP home camera	2 to 4 Mbps	1.3 to 3 Mbps	14 to 45 days
4 MP shop or driveway camera	4 to 8 Mbps	2.6 to 5.5 Mbps	21 to 60 days
4K / 8 MP forensic camera	8 to 16 Mbps	5 to 11 Mbps	14 to 45 days
LPR or high shutter camera	10 to 24 Mbps	7 to 17 Mbps	30 to 90 days

Storage layout	Minimum drives	Usable capacity rule	CCTV planning note
Single disk or JBOD	1	All active drive space	Simple, but footage is exposed to disk failure.
Mirror / RAID 1	2	One drive worth of capacity	Good for small critical systems with short retention.
RAID 5 / single parity	3	Active drives minus one	Efficient for 4 to 8 bay recorders.
RAID 6 or RAIDZ2	4	Active drives minus two	Safer for large disks and long retention windows.
RAID 10	4	About half of active drives	Strong write behavior, but costly for pure capacity.

Common CCTV project	Camera mix	Typical daily storage	Planning reminder
Home doors and driveway	4 x 1080p H.265	0.15 to 0.35 TB/day	Motion recording can stretch small drives.
Retail counter and aisles	8 x 2K H.265	0.8 to 1.6 TB/day	Budget for busy business hours.
Warehouse perimeter	12 x 4 MP H.265	1.5 to 3 TB/day	Night noise and loading docks need buffer.
Parking lot surveillance	16 x 4 MP mixed	2 to 5 TB/day	Continuous recording is often easier to search.

Network item	Practical value	Why it matters	Storage impact
1 GbE uplink	About 750 Mbps safe load	Leaves room for overhead and management traffic.	Does not limit storage unless streams drop frames.
PoE switch uplink	Sum all main streams	Camera bitrate is often higher at night.	Dropped packets can create corrupt or missing footage.
Substream preview	0.1 to 1 Mbps each	Used by apps and multi-camera views.	Usually not counted unless recorded.
Remote backup	Upload-limited	Continuous cloud copy needs steady upstream bandwidth.	Exports may require a separate retention policy.

5 Planning tips

Tip: Size CCTV storage from the main recording stream, not the mobile app preview. Substreams make live viewing lighter, but the recorder usually stores the full main stream for evidence.

Tip: Test one camera at night and during bad weather, then compare the actual Mbps to the calculator. Rain, IR noise, insects, headlights, and foliage are the usual surprises.

When planning CCTV storage, people often makes a series of small mistakes that eventualy cause the system to failing when the recorder hits storage space. A CCTV system fails when the recorder hit storage space before the scheduled retention period is over. To ensure that a CCTV system does not hit storage space, three factor must be considered.

Many people begins with the number of CCTV camera and the resolution of the cameras. Higher resolution allow for clearer footage and enables people to identify peoples face or license plates. However, resolution do not determine the storage needs of the system.

How to Plan CCTV Storage

Storage needs depend on the motion in the scene and the infrared noise in the scene. A 4K camera sees less motion than a 1080P camera in a high traffic area. To determine the data needs of a CCTV system, many company use a storage needs calculator.

Users enter the parameters for the CCTV system into the calculator, and the calculator displays the total data written to the storage disk for the retention period. Using the storage needs calculator, people can change from continuous recording to motion recording, which half the data written to the storage disk. RAID layouts impacts the storage capacity of the CCTV system.

A RAID 5 layout is popular for CCTV systems. The storage calculator will show how much storage space is lose due to the RAID layout. For four drive, the loss of storage space is high.

For eight drives, the percentage of storage space lost to RAID 5 is lower. However, the total amount of storage space lost due to RAID 5 impact the data retention time of the system. The CCTV storage calculator can display the usable storage after RAID 5 array is create.

The CCTV storage calculator can also show how many drive can fail in the RAID 5 array without losing the data recorded. Audio from CCTV camera adds to the storage space need of a CCTV system. A camera can output a maximum of 64 Kbps of audio.

This dont add to the storage space significantly. However, if sixteen cameras include audio function in the CCTV system, this can significantly increase the storage data need of the system. The CCTV storage calculator can display the amount of storage space taken up by audio so that people can decide whether the audio feature is worth the storage space.

The retention time of CCTV footage place additional demand on the storage capacity. CCTV systems may not meet a thirty-day footage retention target if there is high motion in specific area of the CCTV coverage area. The storage space calculator include a growth buffer for situation in which the data rate are higher than the bitrate of the sample footage of the CCTV cameras.

Reference tables show the range of storage space that is take up by CCTV cameras at different resolution using the H.264 and H.265 codecs. These tables assist in comparing the specification of the CCTV cameras with the calculation of the CCTV storage calculator. The RAID table also provide valuable information for CCTV system designer.

Motion recording can take up to half the storage space of continuous recording of CCTV footage. In a high traffic area, motion recording can trigger sixty percent of the time. For this reason, CCTV systems in high traffic areas use motion recording in addition to the H.265 codec to minimize storage space requirement.

The switch from the H.264 to the H.265 codec reduce the data rate by thirty to fifty percent. This is visible in the daily volume data field of the CCTV storage space calculator. The raw storage capacity of the hard drive is not the total amount of data that a CCTV system will have for recording.

The filesystem reserve, the deployment reserve, and the storage space for the exporting of CCTV footage will all take up part of the raw storage capacity. This leave space for the main recording of CCTV footage. This amount can be thirty percent less than the raw storage capacity of the drive.

This calculation help people to avoid the situation in which a CCTV system run out of storage space before the retention period. The CCTV storage space calculator display the live CCTV footage ingest in addition to the recorded volume of the storage space. This allow CCTV system designer to size the network for live CCTV footage as well as the storage space for the recorded CCTV footage.

The goal of CCTV storage planning is to create a margin between the planning of the CCTV system and the actual CCTV footage that will be recorded. The CCTV storage space calculator can be use to determine this margin. Once the number are stable for a group of CCTV cameras, the numbers should of been test with the actual CCTV cameras under night condition.

The bitrate of the actual CCTV cameras may be higher than the expected bitrate. In this case, the growth buffer for the CCTV system should be altered to ensure the CCTV system meet the retention period target of the security system.