OSPF Cost Calculator

Compute OSPF interface cost from bandwidth and reference bandwidth.

Interface bandwidthReference bandwidth

OSPF cost1

Formulacost = max(1, round(ref / bw))

Default reference 10^8. Cost floors at minimum 1.

How to read the result

Cost = reference bandwidth / interface bandwidth, rounded, minimum 1. Default reference is 10^8 (100 Mbps).

Example

100 Mbps / 100 Mbps ref → cost 1

FAQ

Why is fast links cost 1?

Any link at or above the reference bandwidth floors at the minimum cost of 1.

Should I raise the reference?

Yes on gigabit+ networks, e.g. 1 Gbps or 10 Gbps, so fast links stay distinguishable.