Dual Channel Dash Cam Storage Calculator
A dual channel dash cam records the road ahead and behind, so its memory card must hold two video streams at the same time. The Dual Channel Dash Cam Storage Calculator estimates the card capacity needed to retain a chosen number of hours of footage based on the front and rear recording bitrates and the portion of the card available for video.
Use the result as a starting point when choosing a memory card for your dash cam. Actual recording time can vary, so check your camera’s specifications and allow room for files and recording conditions that may increase storage use.
What the Dual Channel Dash Cam Storage Calculator does
This dual channel dash cam storage calculator estimates Required Card Capacity in decimal gigabytes (GB). It combines the average bitrate of the front camera with the average bitrate of the rear camera, then calculates how much space both streams need over your chosen recording period.
The estimate also accounts for the percentage of card capacity available for video. For example, if you enter 90%, the calculation assumes that the remaining 10% is unavailable for the footage you want to retain. That allowance can help account for formatting, other files, or space reserved by the camera.
The calculator assumes that both cameras record continuously at the average bitrates you enter. It estimates the total card capacity needed, rather than simply reporting the size of the video files. Once you have a result, round up to an available card size and confirm that your dash cam supports it.
How to use the Dual Channel Dash Cam Storage Calculator
Enter the following four values using your dash cam’s settings or reasonable estimates based on its specifications:
- Front camera bitrate (Mbps): Enter the average recording bitrate for the front camera in megabits per second. Higher bitrates generally use more storage per hour.
- Rear camera bitrate (Mbps): Enter the average recording bitrate for the rear camera, also in megabits per second. The two cameras may use different bitrates.
- Recording time to retain (hours): Enter how many hours of combined front and rear footage you want to keep before older footage is overwritten.
- Card capacity available for video (%): Enter the percentage of the card you expect to be available for the footage. A lower percentage leaves a larger allowance for other uses of the card.
Read the result beside Required Card Capacity. The result is shown in decimal GB to two decimal places. Choose an available card with at least that capacity, subject to the camera manufacturer’s supported capacity and card requirements.
If you do not know the bitrates, check the dash cam’s documentation or recording settings. You can also estimate an average from sample video files, although files recorded in different conditions may vary in size. Treat any assumed bitrate as an estimate and leave some extra room if retaining the full recording period matters to you.
How the Dual Channel Dash Cam Storage Calculator formula works
The formula adds the two camera bitrates, multiplies the combined rate by the recording time, converts the result to decimal gigabytes, and adjusts for the percentage of the card available for video:
Required Card Capacity = (front bitrate + rear bitrate) × recording hours × 3,600 ÷ 8,000 ÷ (available video percentage ÷ 100)
The conversion uses 3,600 seconds per hour and 8,000 megabits per decimal GB. Dividing by the available video fraction increases the required card size when less than 100% of its capacity is assumed to be usable for footage.
Worked example
Suppose you use the calculator’s illustrative default assumptions:
- Front camera bitrate: 12 Mbps
- Rear camera bitrate: 8 Mbps
- Recording time to retain: 8 hours
- Card capacity available for video: 90%
The combined bitrate is 20 Mbps. Over eight hours, the two streams require an estimated 72 GB of video space before the usable-capacity adjustment:
20 × 8 × 3,600 ÷ 8,000 = 72 GB
With 90% of the card available for video, divide 72 GB by 0.90:
72 ÷ 0.90 = 80.00 GB
The estimated Required Card Capacity is 80.00 GB. Because cards are sold in fixed capacities, select the next available size above the estimate that your camera supports. The example bitrates and 90% allowance are assumptions; your dash cam may record at different rates and use a different amount of card space.
Use cases for the Dual Channel Dash Cam Storage Calculator
Choosing a card for daily driving: Estimate the hours you want to retain across a normal day of travel. If you drive for three hours a day and want several days of footage available, enter the total hours you intend to keep, assuming both cameras record throughout those hours.
Planning for a long trip: A longer journey can fill a card quickly when two cameras record continuously. Enter the expected recording time to see whether your existing card is likely to cover it or whether you should consider a larger supported card.
Comparing recording settings: If your camera documentation lists approximate bitrates for different settings, calculate each option separately. A higher combined bitrate requires more space for the same retention period, while a lower combined bitrate reduces the estimate. Image quality and storage use may both change when you adjust recording settings.
Allowing for other files: Protected clips and other files can occupy part of a card. Reducing the percentage available for video helps you explore how an allowance affects the total card capacity you need. Review and manage saved files according to your camera’s instructions.
Other factors to consider when calculating Required Card Capacity
Variable bitrate: Some dash cams do not record every scene at a constant bitrate. Movement, lighting, weather, and image detail can affect file sizes. An average bitrate is useful for planning, but it cannot guarantee an exact retention time.
Audio and additional files: Audio, protected recordings, snapshots, and other files may increase storage use. Check whether the bitrates you enter include audio. If they do not, leave additional capacity for it.
Formatting and reported capacity: The calculator uses decimal GB, while a computer or device may report capacity using a different unit convention. Formatting and camera-specific storage management can also affect the space available for recordings.
Loop recording: Many dash cams overwrite older unprotected footage when available recording space fills. The calculated time is an estimate of how much continuous footage the card can retain under the entered assumptions, not a promise that a particular clip will remain on the card. Save important footage promptly according to your camera’s instructions.
Parking mode: Parking recording may use continuous video, time-lapse, motion detection, or event-triggered clips, depending on the camera and its settings. If the cameras do not record continuously at the entered bitrates, actual storage use can differ from this estimate.
Card compatibility and endurance: Check the dash cam manufacturer’s supported card capacities, formats, and speed requirements before buying. Dash cams write footage repeatedly, so a card intended for continuous recording may be a suitable choice when it meets the camera’s requirements.
Dual Channel Dash Cam Storage Calculator FAQ
How much storage does a dual channel dash cam need for eight hours?
It depends on both cameras’ bitrates and the space available for video. At the illustrative default rates of 12 Mbps for the front camera and 8 Mbps for the rear camera, eight hours requires an estimated 80.00 GB of card capacity when 90% is available for video.
Do I need to add the front and rear camera bitrates myself?
No. Enter the front and rear bitrates in their respective fields, and the calculator adds them as part of the calculation. Both values should be in megabits per second (Mbps).
Why is the required card capacity higher than the video file size?
The calculation adjusts for the percentage of the card available for video. In the default example, the footage is estimated to occupy 72 GB, but only 90% of the card is assumed to be available for it. That produces a required total capacity of 80.00 GB.
Will a larger card prevent loop recording from overwriting footage?
A larger supported card can generally retain more footage under the same recording conditions, but loop recording can still overwrite older unprotected files once the available space fills. Protect or transfer footage you want to keep.
Can I use this calculator for parking mode?
You can use it for an estimate if the front and rear cameras record continuously during parking mode at known average bitrates. Event-triggered recording and time-lapse modes do not necessarily follow that assumption, so their actual storage needs may differ substantially.