Useful Installer Tools · CCTV

CCTV Storage Calculator

Estimate CCTV DVR/NVR storage from camera count, average bitrate, recording hours, retention days and motion-recording activity. The calculator shows daily storage, raw retention capacity, reserve-adjusted capacity and a practical common HDD capacity target.

System details

Enter the average recording load for the cameras you plan to install. For the best estimate, use the bitrate shown in the actual DVR/NVR or camera settings.

Number of cameras

Retention days

Quick bitrate preset Preset values are planning estimates only. Codec, FPS, scene movement and quality settings can change the real bitrate significantly.

Average bitrate per camera (Mbps)

Recording hours per day

Motion/event activity (%)Use 100% for continuous recording. For motion-only systems, estimate the percentage of the day cameras are actively recording.

Reserve / overhead (%)Extra room for bitrate spikes, metadata, formatting differences and growth. 20% is a practical planning margin.

Planning note: CCTV storage is an estimate, not a guaranteed retention figure. Real usage changes with H.264/H.265 settings, VBR/CBR, FPS, audio, scene movement, smart events and recorder overhead.

Storage estimate

The calculator shows both the raw video requirement and a safer capacity target with your selected reserve.

Per camera / day21.6 GB

All cameras / day172.8 GB

Raw retention need5.18 TB

With reserve6.22 TB

Formula: bitrate × seconds recorded × camera count × retention days, converted from bits to storage bytes. Motion/event activity reduces the effective recording time; reserve is added after the raw requirement.

How to use it

Use the calculator before selecting the DVR/NVR hard drive.

This helps avoid promising 30 days of recording when the installed disk can only hold a fraction of that period.

01Count the camerasEnter the number of channels that will actually record to this recorder.

02Set the retention targetEnter how many days of footage the customer expects to keep before old footage is overwritten.

03Use the real bitrateOpen the camera or recorder encoding settings and use the average mainstream bitrate when possible.

04Choose recording hoursUse 24 hours for full-time recording or reduce this if the recorder has a fixed daily recording schedule.

05Set motion activityContinuous recording uses 100%. Motion-only systems can use a lower estimate, but busy scenes may still record most of the day.

06Keep some reserveExtra capacity protects against bitrate spikes and small differences between calculated and usable disk capacity.

07Check recorder limitsMake sure the DVR/NVR supports the number, size and total capacity of the hard drives you plan to install.

08Prefer surveillance drivesFor continuous CCTV workloads, use drives intended/supported for surveillance recording where appropriate.

09Verify after installationAfter the system has recorded real footage for a few days, compare actual storage usage with the estimate and adjust if needed.