By the SightShield team · · 3 min read
Why the number of days matters
Many problems are noticed late. Stock goes missing and nobody checks until the monthly count. A scratch on a car is found a week later. An employee dispute surfaces after the salary is paid. If your recorder only keeps seven days, the footage you need has already been overwritten.
Recorders overwrite the oldest footage once the disk is full, so the number of days you keep is decided by disk size — and should be decided before you buy.
Typical recording periods
| Property | Common choice | Why |
|---|---|---|
| Home or villa | 15–30 days | Covers trips away and late-noticed incidents |
| Shop or showroom | 30 days | Monthly stock checks and customer disputes |
| Office | 30 days | HR and access questions usually surface within a month |
| Apartment complex | 30 days | Residents report issues late; association needs evidence |
| Factory or warehouse | 30–90 days | Stock audits, dispatch disputes, customer audits |
| Jewellery, finance, cash handling | 60–90 days | Higher value, slower discovery of losses |
What decides how much storage you need
- Number of cameras — storage grows directly with camera count.
- Resolution — a 4MP camera records roughly twice the data of a 2MP camera.
- Compression — H.265 (and its "plus" variants) uses much less space than older H.264.
- Recording mode — 24×7 continuous uses the most; motion- or event-based recording uses far less.
- Scene activity — a busy road or shop floor produces more data than a quiet corridor.
A rough rule of thumb
With H.265, a 4MP camera recording 24×7 typically uses around 20 GB a day, and a 2MP camera about half that. So eight 4MP cameras for 30 days need roughly 8 × 20 × 30 = 4.8 TB — a 6 TB surveillance disk gives some headroom. Treat this as a starting estimate; the recorder settings and scene decide the real figure.
Use our CCTV estimator →Worked example
An office with 12 cameras at 4MP on H.265, recording continuously at roughly 20 GB per camera per day, writes about 240 GB a day. For 30 days that is about 7.2 TB, so an 8 TB disk — or two 4 TB disks — fits with a little headroom. Halve the cameras or the days and the storage halves too. Actual usage varies with scene activity and settings, so check the oldest recording after the first month.
CCTV hard disk calculator →How to get more days from the same disk
- Switch on H.265 or H.265+ in the recorder if your cameras support it.
- Use continuous recording on key cameras (gates, cash counters) and motion or event recording on quiet areas.
- Lower the frame rate on overview cameras — 12–15 frames per second is enough for most security use.
- Add a second hard disk; most 8-channel and larger recorders have space for one.
Check that you are actually getting those days
Open the recorder playback and look for the oldest recording. If you expected 30 days and see 12, either the disk is smaller than planned, a camera setting changed, or the disk is failing. This is one of the first checks done on an AMC visit.
CCTV AMC in Bangalore →Rules that set a minimum
- Karnataka Public Safety Act premises (100 or more people at a time): 30 days.
- CBSE schools: at least 15 days plus a 15-day backup, under Clause 4.7.10.
- PG accommodations in Bengaluru: 90 days under the civic body’s August 2024 order (check for later changes).
- Contracts, insurers and tenancy agreements may set their own periods.
Quick answers
How many days of recording does a 1 TB hard disk give?+
For four 2MP cameras recording 24×7 with H.265, roughly 20–25 days. For four 4MP cameras, around 10–12 days. Actual figures depend on settings and scene activity.
Is there a legal minimum for CCTV recording in India?+
There is no single rule for all private premises. Some sectors and local authorities set their own requirements, so check what applies to your business. Thirty days is a common practical standard.
Does motion recording save space?+
Yes, often a lot on quiet cameras. Keep continuous recording for important views like gates and entrances so nothing is missed.
Can I keep footage longer than the recorder holds?+
Export important clips to a separate drive or cloud storage, or add disks for longer retention.
Is it a problem to keep footage too long?+
Keeping personal data longer than needed is discouraged under data protection principles. Set a retention period that matches your needs and rules.