NIC Throughput Calculator
Calculate achievable throughput of a network interface card given link speed and overhead.
About NIC Throughput Calculator
A NIC's advertised line rate (e.g. 10GbE) is the raw physical-layer signaling rate, not the throughput available to applications — Ethernet/IP/TCP framing overhead (headers, interframe gaps, preambles, and any encapsulation like VLAN tags or tunneling) always consumes a percentage of that rate before payload data gets through. Modern multiqueue NICs also spread traffic across multiple RX/TX queues (typically one per CPU core, distributed via RSS) so that packet processing scales with core count rather than bottlenecking on a single CPU — dividing usable throughput by queue count estimates the per-queue share under evenly balanced load.
Formula
Maximum usable throughput
max_throughput = line_rate × (1 − overhead%)
- R_{line}
- NIC line rate
- o
- protocol/framing overhead fraction
Worked example
With the default values below, NIC Throughput Calculator returns Max Usable Throughput (Mbps) of 9,700.0. Change any input above and every figure here is recalculated in your browser.
Inputs used
- NIC Line Rate (Mbps)minimum 1
- 10,000
- Protocol/Framing Overhead %accepts 0–50
- 3
- RX/TX Queue Countminimum 1
- 8
Results
- Max Usable Throughput (Mbps)
- 9,700.0
- Throughput per Queue (Mbps)
- 1,212.50
- RX/TX Queue Count
- 8
Step by step
- 1Values used
- 2Maximum usable throughput
- 3Max Usable Throughput (Mbps)= 9,700.0
- 4Throughput per Queue (Mbps)= 1,212.50
- 5RX/TX Queue Count= 8
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
How do I check the number of RX/TX queues configured on a NIC?
`ethtool -l <iface>` shows the current and maximum combined/RX/TX queue counts; `ethtool -L <iface> combined <N>` adjusts it (support and limits vary by NIC driver).
Why doesn't traffic distribute perfectly evenly across queues?
RSS (Receive Side Scaling) hashes packet headers (typically the 5-tuple) to select a queue, so a small number of very high-volume flows can concentrate on fewer queues than expected — true even distribution depends on having many diverse flows, not just having many queues configured.
What typical overhead percentage should I assume?
For standard 1500-byte MTU Ethernet with TCP/IP, overhead is commonly in the 2-5% range; it rises with smaller packet sizes (fixed per-frame overhead is amortized over less payload) and with additional encapsulation layers like VLAN tagging, VXLAN, or IPsec.