CAN Bus Load Calculator
Enter your CAN messages and cycle rates to calculate bus load utilization.
CAN Bus Load Calculator
Bus Configuration
Arbitration phase bitrate. CAN FD uses this for header and trailer.
CAN FD only. Used after BRS bit for the data field and CRC.
Calculation Parameters
Average uses a 1.15× multiplier on the stuffable region (industry convention). Worst-case adds the maximum theoretically possible stuff bits per ISO 11898-1. Off disables stuffing entirely — raw frame bits only.
Headroom added on top of the calculated load to account for error/overload frames. Typical 1–3% on noisy buses; leave at 0 for nominal.
CAN FD only. When disabled the data phase stays at the nominal bitrate.
Message Groups
| ID Type | # Messages | Data [bytes] | Cycle [ms] | Bits / Frame | Group Load |
|---|
Data [bytes] — Classical CAN accepts 0–8.
CAN FD accepts 0–8 byte-wise plus 12, 16, 20, 24, 32, 48, 64. Other values are rounded up to the next valid size.
Bits / Frame — total bits transmitted per frame (including stuffing, headers, CRC, IFS).
Bits / Frame — total bits transmitted per frame (including stuffing, headers, CRC, IFS).
Bus Load Result
Total Bus Load:
—
—
Effective Bitrate Used: —
Total Frames / Second: —
Stuffing Mode: —
Sources — Frame size formulas derive from ISO 11898-1.
Classical CAN: base = 47 + 8·DLC (standard) or 67 + 8·DLC (extended) bits, plus stuffing on SOF…CRC.
CAN FD: arbitration phase at nominal rate, data phase at data rate (when BRS enabled), CRC-17 for ≤8 B and CRC-21 for >8 B, plus 4–5 fixed stuff bits in the CRC.
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