iperf3

v3.22Open sourceReleased 29 Sept 2026

The standard tool for measuring real TCP/UDP throughput between two machines — official source from ESnet. By ESnet (Lawrence Berkeley National Laboratory)

macOS
Linux

Official sourceNo bundles

By the ToolsBharat teamUpdated 29 Sept 2026How we check

Quick answer

iperf3 is open source software for macOS and Linux from ESnet (Lawrence Berkeley National Laboratory). The standard tool for measuring real TCP/UDP throughput between two machines — official source from ESnet. Download it only from software.es.net. The latest version we track is 3.22 (29 Sept 2026). ToolsBharat links straight to the publisher's own download page, with no bundled offers.

Latest version:: 3.22 (29 Sept 2026)
Publisher:: ESnet (Lawrence Berkeley National Laboratory)
Official site:: software.es.net
Licence:: Open source — BSD 3-Clause (LBNL / UC Regents)
Requirements:: Linux, macOS, FreeBSD and other Unix-like systems (source or OS packages); no official Windows binary

Our verdict

iperf3 measures what a link can really carry: run it as a server on one machine and as a client on another, and it reports throughput, jitter and loss. Technicians use it to prove a fibre or point-to-point link is delivering its rated speed, without the internet getting in the way. The official project is ESnet's, which publishes source releases (3.22 is current) and is packaged by most Linux distributions. ESnet states it does not distribute binary packages — including for Windows — and that third-party builds are the responsibility of whoever makes them. iperf.fr is a third-party site, not the official project.

Key features

TCP, UDP and SCTP throughput tests
Reports jitter and packet loss for UDP
Reverse and bidirectional modes; JSON output
Packaged in most Linux distributions

Pros

Pro: Industry-standard results
Pro: Open source with a published SHA-256 for each source release

Cons

Con: No official Windows build from ESnet
Con: Command-line only

What's new in 3.22

See what changed in 3.22 in the official release notes

Version history

Version 3.22Latest
29 Sept 2026
SHA-256
The developer does not publish one
Source
Release notes

Official downloads by platform

For macOS, use the Download button. Other platforms go straight to the publisher's own page or official store.

Linux — official downloadsoftware.es.net(opens software.es.net in a new tab)

Requirements

OS: Linux, macOS, FreeBSD and other Unix-like systems (source or OS packages); no official Windows binary
Architecture: Any (built from source)

Licence

Type: Open source
Licence: BSD 3-Clause (LBNL / UC Regents)
Publisher: software.es.net

Where these facts come from

Checked 30 Oct 2026

FAQ

Where do I download iperf3 for Windows?

ESnet, the official developer, does not distribute Windows binaries; its page notes that third-party Cygwin builds exist and that those third parties are responsible for them. If you use one, check its source carefully. On Linux, install iperf3 from your distribution's package manager.

Is iperf.fr the official iperf site?

No. iperf.fr is run by a third party. The official iperf3 project is ESnet's at software.es.net/iperf and github.com/esnet/iperf.

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