How long does a 32GB microSD card record at 5MP?
A 32GB microSD card in a 5MP camera recording continuously in H.265 at about 4 Mbps holds roughly 0.7 days of footage before it starts overwriting. Recording only on motion, at around two hours of activity a day, the same card covers about 8 days.
How this is worked out
days = (card GB x 1,000 MB x 0.93 usable) / (bitrate Mbps x 450 MB per hour x hours per day)
Card capacity is quoted in decimal gigabytes and the usable fraction after formatting is a little over 90 percent, so a 32GB card provides about 30GB of actual recording space.
| Card size | Continuous | Motion, about 4 h a day | Motion, about 2 h a day |
|---|---|---|---|
| 32 GB | 0.7 | 4.1 | 8.3 |
| 64 GB | 1.4 | 8.3 | 16.5 |
| 128 GB | 2.8 | 16.5 | 33.1 |
| 256 GB | 5.5 | 33.1 | 66.1 |
| 512 GB | 11 | 66.1 | 132.3 |
| Storage | Capacity | Days at 5MP, one camera | What it is for |
|---|---|---|---|
| microSD 32GB | 32 GB | 0.7 | On camera fallback if the network or recorder fails. |
| 1 TB drive | 1,000 GB | 21.5 | A small recorder, or one camera with long retention. |
| 4 TB drive | 4,000 GB | 86.1 | The standard recorder drive for a whole system. |
Use a high endurance card or expect it to fail
A standard microSD card is designed for a phone, where it is written occasionally and read often. A security camera writes to it continuously, forever, and a normal card will fail within months of that duty. High endurance cards use different flash and a controller built for sustained writing, and they are sold specifically for dash cameras and security cameras.
The failure is also quiet. A card that has worn out frequently reports success while writing nothing recoverable, so the first sign of the problem is usually an empty card on the one occasion the footage mattered. Check that recordings actually play back every few months.
What a card is genuinely good for
A card in the camera keeps recording when the network is down, the recorder has failed, or the power to the house has gone but the camera is on a battery. That redundancy is worth having, and it is the reason most PoE cameras include a card slot even though they are wired to a recorder.
For a camera with no recorder at all, a card is the entire storage system, and at 5MP a 32GB card gives about 0.7 days of continuous retention. Whether that is enough depends on how quickly you would notice something had happened.
High endurance cards at this capacity
Standard cards are not rated for continuous recording and fail quietly. Every card here is a high endurance type.
SanDisk 128GB High Endurance Video microSDXC Card with Adapter
$36.99Half the capacity at well under half the price, which is enough when the card is a fallback for a network outage rather than the primary store.
- Capacity
- 128 GB
Prices change often.
Integral 128GB High Endurance microSD Card for CCTV and Security Cameras
$38.95Sold specifically for continuous security recording rather than for phones, at the lowest price per gigabyte in this group.
- Capacity
- 128 GB
Prices change often.
SanDisk 256GB High Endurance microSD Card with Adapter
$69.99The card most commonly specified by camera makers for continuous recording, and the capacity that gives a single 4K camera roughly a week.
- Capacity
- 256 GB
Prices change often.
PNY 256GB PRO Elite High Endurance microSDXC Flash Memory Card
$79.99A direct alternative at the same capacity, worth checking when the SanDisk is out of stock.
- Capacity
- 256 GB
Prices change often.
Common questions
How many days will a 32GB card record at 5MP?
About 0.7 days recording continuously, or roughly 8 days if the camera only records on motion and sees around two hours of activity a day. After that it overwrites the oldest footage, so it never stops recording, it just stops being able to look further back.
Do I need a high endurance microSD card for a security camera?
Yes. A standard card is not built for continuous writing and typically fails within months in a camera, often silently, reporting success while saving nothing usable. High endurance cards use flash and controllers designed for exactly this duty and cost only a little more, which makes them the only sensible choice for any camera recording to a card.
Is a microSD card enough, or do I need an NVR?
For one or two cameras with modest retention needs, a card can be enough. For a whole system it is not: a 32GB card holds about 0.7 days from a single camera, while a 4 TB recorder drive holds weeks from eight. A card is also inside the camera, so anyone who removes the camera removes the evidence with it.
What card size should I buy?
Buy the largest high endurance card the camera supports, because the price difference is small against the cost of the camera and retention is the thing people regret being short of. Check the camera specification for its maximum supported capacity first, since many cameras cap out below the largest cards available.
Get the system planning sheet
The camera count, storage and PoE budget worksheet, plus the wiring checklist, as one printable page.
Keep going
- microSD recording days calculator
- NVR storage calculator
- Best microSD cards for security cameras
- Card storage compared with a recorder
- How long does a 32GB microSD card record at 8MP (4K)?
- How long does a 32GB microSD card record at 4MP (1440p)?
- How long does a 64GB microSD card record at 2MP (1080p)?
- How long does a 128GB microSD card record at 2MP (1080p)?
Before you point a camera at anything. Aim cameras at your own property and your own boundary, never into a neighbour's windows or across their garden. Cameras in bedrooms, bathrooms, or anywhere else a person reasonably expects privacy are a serious legal problem, and that includes guests, lodgers and anyone who works in your home. Audio is legally different from video, many US states require the consent of every party to a recorded conversation, and several recorders capture audio by default, so check your own state before you enable it. Some places require visible notice that recording is taking place, and landlords and homeowner associations often impose their own rules on top. This is researched general information and not legal advice, and the law varies by state and by country.
And once it is installed. Change every default password, keep the firmware updated, and be clear with yourself about where the footage goes: a cloud camera means a third party holds recordings of your home, while a local recorder keeps them in your house. That is a genuine buying consideration, not a technicality.