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ARP Table Size Calculator

Estimate ARP table requirements, memory usage, and ARP traffic rates

Average number of active hosts in each subnet. Each host generates at least one ARP entry on every Layer 3 device in the subnet.
Total number of subnets (SVIs/VLAN interfaces) on the device. Each subnet maintains its own ARP table.
How long ARP entries remain before being refreshed. Default is 240 seconds (4 minutes) on Cisco IOS. Longer timeouts reduce ARP traffic but may keep stale entries.
seconds
bytes

ARP Table Results

Total ARP Entries
Memory Required
ARP Requests/sec (steady state)
ARP Bandwidth (requests)
Peak ARP Storm Estimate
ARP Timeout
References:
ARP (RFC 826) - 28 bytes per entry (IP + MAC + metadata)
Cisco default ARP timeout: 240 seconds
ARP request/reply: 28-byte payload in 42-byte Ethernet frame