Dashcam Storage Calculator — Card Size vs Recording Time
A dashcam storage calculator estimates how long a memory card records before loop recording overwrites the oldest files — the number that decides whether footage from last Tuesday still exists.
Quick answer: At 1080p30 (~8 Mbps), one hour of dashcam footage is about 3.6 GB, so a 128 GB card keeps roughly 35 hours of driving — about two weeks of a 2½-hour daily commute, or two days of continuous recording.
1 = front only, 2 = front + rear
Check the camera/NVR spec sheet
Typical commute is 1–2 h
Loop recording keeps the newest footage
| Storage | Retention |
|---|---|
| 32 GB | 2.12 days |
| 64 GB | 4.23 days |
| 128 GB | 8.47 days |
| 256 GB | 16.9 days |
| 512 GB | 33.9 days |
| 1 TB | 66.1 days |
| 2 TB | 132 days |
| 1080p30 (~8 Mbps) | ~3.6 GB per hour |
|---|---|
| 1080p60 (~16 Mbps) | ~7.2 GB per hour |
| 4K30 (~30 Mbps) | ~13.5 GB per hour |
| 64 GB card | ≈ 17 h at 1080p30 · ≈ 4.7 days of 2 h driving |
| 128 GB card | ≈ 35 h at 1080p30 · ≈ 9.5 days of 2 h driving |
| 256 GB card | ≈ 71 h at 1080p30 · ≈ 19 days of 2 h driving |
Loop recording changes the question
A dashcam never “fills up” — when the card is full, the oldest clip is overwritten. The real question is not capacity but retention: how far back can you still find footage? Most drivers want at least seven days, which at two hours of driving per day means 14 hours of footage, comfortably inside a 64 GB card — but a two-camera setup at 1080p60 needs 32 GB more.
Two cameras, parking mode and heat
A front-and-rear kit doubles the bitrate; parking mode with motion events can add a few gigabytes a day on top. High temperatures make cards fail early, so dashcams want high-endurance cards rated for continuous writing — a standard card that dies after a year of summer heat usually shows up as missing clips rather than as an error message.
Choosing the card and the resolution
Resolution is a safety feature — number plates need pixels — so keep 1440p or 4K for the front camera rather than trading quality for card life. Instead, size the card for the retention you want: 128 GB covers about nine days of two-hour commutes at 1080p30, 256 GB about nineteen. Format the card in the camera (not on a computer) and reformat every few months.
When to use this calculator
- Choosing a card size for a new dashcam.
- Checking how far back footage is retained before buying a bigger card.
- Estimating storage for a front-and-rear two-channel setup.
- Planning around parking mode and motion-triggered recording.
- Working out whether a 4K dashcam needs an upgraded card.