EIGRP Metric
Calculate the composite EIGRP metric from bandwidth, delay, reliability and load.
About EIGRP Metric
EIGRP computes a composite metric from the slowest (minimum) bandwidth along the entire path and the cumulative delay of every link in the path, combined using tunable K-value weights. With Cisco's default K-values (K1=1, K3=1, and K2=K4=K5=0), the formula reduces to 256 times the sum of a bandwidth term (10,000,000 divided by the minimum bandwidth in Kbps) and a delay term (the total delay in tens of microseconds). Because it uses the single slowest link rather than summing bandwidth, and adds cumulative delay, EIGRP's metric reflects real path characteristics more richly than RIP's simple hop count, while remaining computationally lighter than full link-state flooding.
Formula
EIGRP composite metric (default K-values)
metric = 256 × ((10^7 / min_bandwidth_Kbps) × K1 + (total_delay / 10) × K3)
- B_min
- Minimum bandwidth along the path (Kbps)
- D_sum
- Cumulative delay (tens of microseconds)
- K_1
- Bandwidth weight (default 1)
- K_3
- Delay weight (default 1)
Worked example
With the default values below, EIGRP Metric returns EIGRP Composite Metric of 3,072,000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Minimum Bandwidth Along Pathminimum 1 Kbps
- 1,000 Kbps
- Cumulative Delayminimum 0 µs (tens)
- 2,000 µs (tens)
- K-Value Profileone of Default (K1=1, K3=1, others 0), All K-values = 1 (unusual)
- Default (K1=1, K3=1, others 0)
Results
- EIGRP Composite Metric
- 3,072,000
- Bandwidth Term (10^7 / min_bw)
- 10,000.00
- Delay Term (sum of delay / 10)
- 2,000.00
- Note
- Default K-values (K1=1, K3=1, K2=K4=K5=0) applied — the standard EIGRP composite metric formula.
Step by step
- 1Values used
- 2EIGRP composite metric (default K-values)
- 3EIGRP Composite Metric= 3,072,000
- 4Bandwidth Term (10^7 / min_bw)= 10,000.00
- 5Delay Term (sum of delay / 10)= 2,000.00
- 6Note= Default K-values (K1=1, K3=1, K2=K4=K5=0) applied — the standard EIGRP composite metric formula.
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
Why does EIGRP use the minimum bandwidth instead of summing all link bandwidths?
A multi-hop path can never move data faster than its slowest link — that link is the bottleneck for the entire path — so EIGRP correctly uses only the minimum bandwidth encountered along the route rather than summing or averaging bandwidths, which would misrepresent the path's true throughput ceiling.
What do the EIGRP K-values control?
K1 through K5 weight the contribution of bandwidth, load, delay, reliability, and MTU respectively to the composite metric formula. Cisco's default enables only K1 (bandwidth) and K3 (delay), effectively ignoring load, reliability, and MTU unless an administrator explicitly changes the K-value profile — all routers in an EIGRP domain must use matching K-values or they cannot form neighbor relationships.
Why is the metric multiplied by 256?
The scaling factor of 256 originates from EIGRP's predecessor, IGRP, which used an 8-bit (0-255) metric internally; EIGRP retained backward compatibility with IGRP by scaling its wider composite metric by 256, preserving the ability to redistribute routes between the two protocols with a consistent conversion factor.