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).

If you need to record CAN FD data offline, the CANedge family supports CAN FD on both channels. Pick the variant that fits your data offload need:

• CANedge1: Logs 2 x CAN/CAN FD to an 8-32 GB SD card - ideal for blackbox-style logging where the SD card is collected manually
• CANedge2: Adds WiFi for automatic upload of the recorded CAN FD data to your own server (self hosted or cloud)
• CANedge3: Adds 3G/4G LTE + internal GNSS/IMU for telematics-style CAN FD logging from vehicles in the field

For an overview, see our CAN FD data logger intro.

If you need to stream CAN FD data in real-time, the CANsub interfaces let you stream 2-4 x CAN/CAN FD channels via USB or Ethernet directly into webCAN in your browser - with zero software installation:

• CANsub.2: Streams 2 x CAN/CAN FD via USB or Ethernet
• CANsub.4: Streams 4 x CAN/CAN FD via USB or Ethernet - ideal for multi-bus test setups

Once streaming, you can DBC decode CAN FD frames on the fly in webCAN into named signals - or send custom CAN FD transmit sequences for OBD2/UDS/J1939 requests.

The CANmod family lets you add sensor data to your CAN FD network as native CAN frames. Each CANmod's primary CAN bus is CAN FD compatible - meaning it can output its sensor data directly onto a CAN FD network:

• CANmod.gps: Streams GNSS position + 3D IMU (accel/gyro) data as CAN frames on the CAN/CAN FD bus
• CANmod.temp: Streams 4 x thermocouple temperature readings as CAN frames on the CAN/CAN FD bus
• CANmod.input: Streams 8 x analog/digital/pulse input readings as CAN frames on the CAN/CAN FD bus
• CANmod.router: Aggregates up to 4 x CAN/CAN FD buses onto a single CAN FD output