The Short Answer
iperf3 is not officially supported on Windows. Its maintainers at ESnet develop and test it for Linux, FreeBSD, and macOS — the Windows builds floating around the internet are unofficial third-party compiles, most of them years old. If you need reliable throughput testing on Windows, use a tool that treats Windows as a first-class platform.
Three Real Problems With iperf3 on Windows
**1. There is no official Windows build** — ESnet does not publish Windows binaries. The most widely downloaded builds come from third-party sites and lag years behind the current release, which means known bugs and missing fixes. You are benchmarking your network with a tool nobody is maintaining for your platform.
**2. It runs through an emulation layer** — Classic Windows builds of iperf3 rely on Cygwin, a POSIX compatibility layer that translates Unix system calls to Windows ones. That translation sits directly in the data path of your test. Microsoft's own networking team has publicly recommended against using iperf3 on Windows for exactly this reason: results can misrepresent what the Windows networking stack actually does.
**3. It measures less than you think** — Even where iperf3 works well, it reports throughput, jitter, and summary packet loss. It does not measure latency under load, connection recovery, or data integrity. A link can post a beautiful iperf3 number and still ruin VoIP calls with loaded latency that the test never saw.
What Microsoft Recommends Instead
Microsoft's networking engineers point Windows users at two of their own tools:
ntttcp — Microsoft's throughput benchmark. Solid on Windows, and there is a separate Linux edition, but the two editions historically have not interoperated cleanly — testing Windows-to-Linux requires matching versions and careful flag choices.
ctsTraffic — powerful for Windows-to-Windows scenarios, but there is no Linux side at all.
Both are credible tools. Both also assume a Windows-centric world, come as bare command-line utilities, and leave you to assemble your own reporting.
Where Litmus Fits
We built Litmus because our consulting work constantly needed one tool that worked the same on both sides of a mixed environment:
Native on Windows and Linux — a self-contained executable for each, no Cygwin, no runtime, no installer.
Cross-platform by design — run the server on Linux and the client on Windows, or any other combination.
Measures the full picture — throughput, idle and loaded latency, RFC 3550 jitter, per-packet loss, and CRC32 data integrity, graded A–F.
Reports built in — every test can produce a PDF report ready for a change ticket, SLA dispute, or handover pack.
Litmus is free, with a full GUI on Windows and an interactive terminal UI on Linux. Download it from our tools page and run your first two-machine test in under a minute.
The Bottom Line
iperf3 remains a great tool on the platforms it was built for. On Windows, the honest position — shared by its maintainers and by Microsoft — is that you should reach for something else. Whether that is ntttcp for a Windows-only environment or Litmus for mixed Windows/Linux networks with proper reporting, test with a tool that was actually built for the job.
Written by Ewan Macpherson
Founder & Lead Network Consultant
Ewan has spent over 15 years designing, building, and operating enterprise networks across Australia. More about the team.
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