How to Calculate Video Recording Duration Storable on TF Cards for Surveillance Cameras-Knowledge Encyclopedia-Shenzhen Kai Mo Rui Electronic Technology Co. LTD

How to Calculate Video Recording Duration Storable on TF Cards for Surveillance Cameras

Source：Shenzhen Kai Mo Rui Electronic Technology Co. LTD2026-08-03

To figure out how long surveillance footage can be saved on a TF memory card, comprehensive calculation shall be carried out following the steps below, with multiple influencing factors taken into consideration.

1. Basic Calculation Formulas

Total Recording Days = (TF Card Capacity × 1024) ÷ Daily Video Storage Consumption

Daily Video Storage Consumption = (Main Bitrate (Mbps) ÷ 8) × 3600 × 24 ÷ 1024

Unit Conversion Rules:

1GB = 1024 MB; 1 Mbps = 0.125 MB per second

Calculation Example

Conditions: Camera main bitrate = 4 Mbps, 128GB TF card

Daily occupied storage = (4 ÷ 8) × 3600 × 24 ÷ 1024 ≈ 42.2 GB/day

Total recording days = (128 × 1024) ÷ (42.2 × 1024) ≈ 30.3 days

2. Key Variables & Reference Parameters

Recommended Main Bitrate by Resolution

2MP (1080P): 2 ~ 4 Mbps
3MP (2K): 4 ~ 6 Mbps
4MP (4 Megapixel): 6 ~ 8 Mbps

Storage Duration Reference Chart (Based on 4 Mbps Bitrate)

表格

TF Card Capacity	Continuous Recording	Motion-Activated Recording*
32GB	Approx. 7 Days	Approx. 14 Days
64GB	Approx. 14 Days	Approx. 28 Days
128GB	Approx. 30 Days	Approx. 60 Days
256GB	Approx. 60 Days	Approx. 120 Days

*Motion recording calculated with 50% invalid static footage filtered out

3. Factors That Affect Recording Duration

Resolution & Frame Rate: 1080P footage consumes 50%~100% more storage space than 720P.
Video Coding Compression: H.265 saves roughly 30% storage compared with H.264.
Recording Mode: All-day continuous recording only lasts half the time of motion detection recording.
Scene Complexity: Scenes with frequent moving objects and drastic light changes will raise the actual bitrate.

4. Tips to Extend Recording Time

Prioritize cameras equipped with H.265 video encoding
Enable motion detection recording or scheduled recording mode
Format the TF card regularly to prevent file fragmentation
Adopt industrial-grade TF cards featuring high temperature resistance and wear resistance

With the above formulas and adjustable variables, you can quickly estimate the storage cycle for various application scenarios. It is advised to reserve 10%~20% spare storage space for actual onsite deployment.

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