CAN / CAN FD Frame Length and Transmission Time Calculator
CAN / CAN FD Frame Length and Transmission Time Calculator
Compute frame bit count (including bit stuffing) and transmission time from baud rate and frame format for bus load estimation.
Frame and Baud Rate
Frame Format
Payload bytes: 8
Worst-case bit stuffing estimation
Baud Rate
Results and Frame Waveform
Segments are proportional to transmission time; not an exact waveform. With BRS on, Data/CRC segments are shortened by the accelerated baud rate.
Arbitration rate: 1 Mbps; Data rate: 5 Mbps
Time Scale
μs/div
8.0 px/μs · width 406pxBus load: If this message is sent with period T, load ≈ (50.80 μs / T) × 100%. E.g. at 10 ms period ≈ 0.51%.
SOF (1 bit, Arbitration rate) ID11 (14 bit, Arbitration rate) CTRL+BRS (6 bit, Arbitration rate) Data (80 bit, Data rate) CRC (21 bit, Data rate) ACK+EOF+IFS (15 bit, Arbitration rate)
Overview
This tool computes the bit count (including bit stuffing) and transmission time of a CAN or CAN FD frame from baud rate and frame format (standard/extended, DLC, stuffing mode). It also shows a waveform sketch to compare time cost of different messages and estimate bus load.
Inputs
| Parameter | Description |
|---|---|
| Protocol | CAN 2.0 or CAN FD |
| Frame type | Standard (11-bit ID) or Extended (29-bit ID) |
| DLC | Data length code; 0–8 for CAN 2.0; 0–8, 12, 16, 20, 24, 32, 48, 64 for CAN FD |
| Bit stuffing | Worst case (recommended) or Ignore |
| Arbitration baud rate | Arbitration phase bit rate (bps) |
| Data baud rate | Data phase bit rate (bps), CAN FD only |
Outputs
- Total frame bits: Including bit stuffing and inter-frame space
- Arbitration / Data phase bits: Shown separately for CAN FD
- Transmission time: In μs and ms for load estimation
- Waveform sketch: SOF, identifier, control, data, CRC, ACK, EOF by bit proportion (schematic only)
Bus load
If the message is sent with period T (e.g. 10 ms):
text
Load ≈ (Transmission time / T) × 100%The tool gives an example such as “e.g. ~x% at 10 ms period”.