Measure headers, framing, and timing overhead precisely. Compare payload sizes, acknowledgments, and encapsulation effects easily. Optimize transfer efficiency with clearer packet-level bandwidth insight today.
This page uses a single-column flow overall. The calculator fields below switch to three columns on large screens, two on medium screens, and one on mobile.
These sample rows show how payload size, IP version, encapsulation, and retransmissions can change overall transport efficiency.
| Scenario | Payload / Packet | IP Header | Extra Encapsulation | ACK Ratio | Total Wire Bytes | Overhead % | Efficiency % |
|---|---|---|---|---|---|---|---|
| Small Payload / IPv4 | 536 bytes | 20 bytes | 0 bytes | 2:1 | 12,774,670.00 bytes (12.18 MB) | 17.9176% | 82.0824% |
| Standard MTU / IPv4 | 1,460 bytes | 20 bytes | 0 bytes | 2:1 | 11,326,210.00 bytes (10.80 MB) | 7.4204% | 92.5796% |
| Encapsulated / IPv6 | 8,960 bytes | 40 bytes | 24 bytes | 2:1 | 10,837,336.42 bytes (10.34 MB) | 3.2441% | 96.7559% |
1) Data packets
Data Packets = ceil(Total Application Data / Payload Per Packet)
2) Wire overhead per packet
Wire Overhead Per Packet = TCP Header + IP Header + Layer 2 Header + VLAN + FCS + Preamble/SFD + IFG + Extra Encapsulation
3) Initial data wire bytes
Data Wire Bytes = Total Application Data + (Data Packets × Wire Overhead Per Packet)
4) ACK traffic
ACK Packets = ceil(Data Packets / ACK Ratio)
ACK Wire Bytes = ACK Packets × Wire Overhead Per Packet
5) Retransmission impact
Retransmitted Data Packets = ceil(Data Packets × Retransmission %)
Retransmission Bytes ≈ Retransmitted Data Packets × Average Data Frame Bytes
6) Totals
Total Wire Bytes = Data Wire Bytes + ACK Wire Bytes + Retransmission Bytes
Total Overhead Bytes = Total Wire Bytes − Total Application Data
7) Efficiency and goodput
Efficiency % = (Total Application Data / Total Wire Bytes) × 100
Overhead % = 100 − Efficiency %
Goodput = Useful Data / Transfer Time
This model treats ACK packets as zero-payload control frames and counts timing-related Ethernet costs such as preamble and inter-frame gap in true on-the-wire usage.
It includes TCP header bytes plus related wire costs you enter, such as IP header, Layer 2 framing, VLAN tags, FCS, preamble, inter-frame gap, and optional encapsulation. The tool also adds ACK traffic and retransmission effects when enabled.
Preamble/SFD and inter-frame gap do not appear inside payload captures, but they still consume link time. Including them gives a more realistic wire-rate view, especially when comparing packet sizes or estimating transfer efficiency on busy links.
Fixed headers and framing stay almost the same regardless of payload size. When payload shrinks, that fixed cost occupies a larger share of every packet. The result is more packets, more ACKs, and a higher percentage of overhead.
A value of 2 is a common delayed-ACK assumption, meaning one ACK for roughly every two data packets. Use 1 when you want an ACK for every segment, or a different value to model specialized environments.
No. It is a planning and estimation calculator. Real traffic can differ because of MSS negotiation, TCP options, SACK behavior, offloading, congestion control, delayed ACK logic, and application burst patterns. Captures still validate production behavior.
It represents the approximate share of data packets that must be sent again because of loss or errors. The calculator estimates retransmission bytes from the average data frame size, giving a quick planning view rather than a forensic simulation.
Yes. Put additional wrapper bytes into the extra encapsulation field. That helps model GRE, VXLAN, IPsec-like overhead, or other overlays. You can also add VLAN bytes separately for more granular link-layer accounting.
Efficiency is the percentage of total wire bytes that are useful application data. Goodput converts that useful share into a transfer rate using the line speed you entered, so it reflects how much real payload is delivered over time.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.