Goodput Calculator

Calculate goodput — the application-level useful data rate excluding retransmissions and overhead.

About Goodput Calculator

Goodput is the application-level useful data rate — what remains after subtracting protocol overhead (headers, framing, control packets) and retransmissions from the raw link rate. It represents what the end user or application actually experiences as usable throughput.

Formula

Goodput

goodput = link_rate * (1 - overhead%) * (1 - retransmission%)

R: Link rate
o: Overhead fraction
r: Retransmission fraction

Worked example

With the default values below, Goodput Calculator returns Goodput (Useful Data Rate) of 931.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Link Rateminimum 0.1 Mbps: 1,000 Mbps
Protocol Overheadaccepts 0–50 %: 5 %
Retransmission Rateaccepts 0–50 %: 2 %

Results

Goodput (Useful Data Rate): 931.00 Mbps
Overall Efficiency: 93.10%
Bandwidth Lost to Overhead + Retransmissions: 69.00 Mbps

Step by step

1Remove overhead= 950 Mbps
2Remove retransmissions= 931 Mbps
3Wasted bandwidth= 69 Mbps

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 does goodput differ from throughput?

Throughput measures total data rate including retransmissions and protocol overhead, while goodput measures only the unique, useful application data successfully delivered — throughput can be high while goodput is low if many packets need retransmission.

What typically reduces goodput the most?

High retransmission rates (from packet loss) have the largest impact, because each retransmission wastes bandwidth carrying data already sent once AND triggers TCP congestion control which further reduces sending rate.