Last update: July 1st, 2026
We really appreciate all the feedback that we get through our contact form each day. A question that comes up quite often is “What is the maximum recording time of camera XY”, or, “How much recording time do I get with a 256GB card (512GB card, etc.)?”.
The answer to this question applies not only to dashboard cameras, but to oth digital video camera as well such as action cams, body cams, and so on.
This article will show you how to calculate exactly how much video footage you are going to get with any given camera setup. Plus, we will also give you a simple rule-of-thumb formula that allows you to all but calculate the recording time in your head.
NOTE: If you don’t care about the math and just want a quick and dirty formula to calculate the recording time of any camera, just skip the next couple of paragraphs and continue reading at “Quick Formula”.
High-end Viofo memory cards are built to last a lifetime. Sizes: 64, 128, 256, and 512GB
The recording capacity of a video camera depends on several factors. One factor is obviously the size of the memory card (SD card) used. The other factor is the camera’s bit rate. When you know both of these, you can calculate the maximum recording capacity using a simple formula.
Bear in mind that you can reduce the bit rate by lowering video resolution. For example, if your camera’s maximum resolution is 1440 but you set it to 1080p, obviously this will allow you to record more video footage than when you record in 1440p mode.
Calculating Recording Time
So based on the size of the memory card and the bit rate, how can we calculate the total recording time?
Let’s say you are using a Viofo A229 Plus 2CH with a 512 GB SD card, which is the maximum that this dashboard camera can handle.
You have two video channels (front and rear), and you are running both channels at their at maximum resolution of 1440p for optimum video quality. As you can check in our review of the A229 Plus that we linked above, the bit rate your camera is recording is 29 Mbps for the front channel, and 24 Mbps in the rear.
This results in a total bit rate of 29 Mbps + 24 Mbps = 53 Mbps.
Mbps means “Megabit per second”, so each second of video consumes 53 million bits.
Your memory card has a capacity of 512 GB. That’s 512 Gigabyte, or 512 billion bytes. 1 byte has 8 bits, so the capacity in bits is 512*8=4096 Gbits. Divide this by 15 Mbits (15 million bytes), and the result is the number of seconds you can record.
512,000,000,000*8⁄53,000,000 = 512,000*8⁄53 = 4,096,000⁄53 = 77,283.02
77,283.02 seconds divided by 60 are 1288.05 minutes, which equals 21.47 hours. In other words, with a 512 GB card, the Viofo A229 Plus can record continuously for over 21 hours before it will automatically start to overwrite the oldest footage.
So with GB being the card size in GB, Mbps the bit rate in Mbps, and s the recording time in seconds, our formula is
card capcaity in GB*8*1000⁄total bit rate in Mbps = recording time in seconds
or to get the result in hours directly
GB*8*1000⁄Mbps*3600 = 2.222*GB⁄Mbps
Of course, dash cams have loop recording. so your A229 Plus won’t simply stop recording after 21 hours. Instead, it starts overwriting the oldest files after that time. So 21+ hours is the total amount of video footage that will fit on a 512 GB card.
Quick Top-Of-Your-Head Formula
If you just need a quick approximation of the total recording time in hours, of a dash cam or any other digital video camera, you can use this quick formula:
2 * GB⁄Mbps
In other words, take the memory card capacity in GB, divide it by the bit rate, and multiply the result by 2.
The result will be about 10% less than the theoretical maximum recording time. There will also be some formatting data on the card, and the space is not always used optimally. Thus, leaving a 10% buffer for overhead gives you a very good approximation of your actual recording time.
Always Use High Endurance SD Cards In Video Surveillance
If you use a regular memory card in a video surveillance camera, you may find out that it won’t last very long, in some cases only a few weeks or months. Why is this?
Security cameras — no matter whether it’s a dash cam, a security camera, a body cam, or any other type of video surveillance — continually write to the SD card, often even 24/7. Once the card is full, the oldest content is overwritten, and a new writing cycle begins.
Each time the data is overwritten, the flash memory on the card degrades a little bit. Regular memory cards are not designed for this type of heavy use. High endurance cards are specifically made for continuous recording, and will survive much longer.
Sandisk has good quality SD cards for an affordable price
Obviously, the bigger the memory card is, the more data it will hold. As a result, there will be less writing cycles, so the card will last longer. For maximum SD card life, we recommend you get the largest card that your camera supports.
Most dash cams support 256GB or more these days. If your camera supports it, it’s preferable to get a larger card though: Statistically speaking, 512GB will last roughly twice as long in terms of overall lifetime of the memory card, and 1TB (if your camera can handle it) will last you four times as long.
For a side-by-side overview of which dash cam can handle the largest memory card, have a look at our comparison tables. They list the maximum supported SD card size of each camera.
If you’re interested in the technical details of SD cards and how they work, check out this article that goes a lot deeper into the specifics.