CAN FD Calculator - Efficiency and Average Baud Rate

The CAN FD calculator tool lets you compare Classical CAN bus frames vs. CAN FD frames (Flexible Data-rate). For a full overview of each of the CAN FD and CAN frame fields, see our intro to CAN bus and intro to CAN FD.

In particular, the tool calculates the efficiency of the CAN and CAN FD frames as a function of the number of data bytes in the frame payload. The CAN frame efficiency is calculated as the payload #bits divided by the total #bits. In other words, it is a measure of how efficient a frame structure is in terms of it's ability to transport CAN bus payloads. As evident, the CAN FD frame is less efficient than the Classical CAN frame if the total payload is 8 data bytes or below. On the other hand, if the CAN FD frame has 12+ data bytes, it is more efficient than the Classical CAN frame.

The CAN FD tool also calculates the average baud rate for the Classical CAN vs. CAN FD frames. For the Classical CAN frame, this simply equals the arbitration bit rate. For the CAN FD frame, the efficiency calculation formula is as below:

Finally, the tool provides a dynamic visualization of each of the frames to reflect how the frames compare at different settings.

Note that the calculator excludes stuff bits for simplicity, though it enables the inclusion/exclusion of 'Fixed Stuff Bits' in the SBC (Stuff Bit Count) field (2 bits) and CAN FD CRC field (4 bits).

You can also check out our original CAN FD calculator tool via below Google Sheet: