The XDA story about a $5 Ethernet cable halving somebody’s home internet was a familiar feeling. The line you pay for is a promise; what the device actually receives is an empirical question. Until you measure both sides of the wire, you can’t tell whether the slowdown is the ISP, the router, the switch, the cable, or the access point. The right tool depends on what you’re measuring: the WAN side, the LAN side, or the path between two specific devices.
We tested seven internet speed test apps on Windows, macOS, and Linux, covering everything from the polished consumer speed test to the open-source CLI tools network engineers actually run before they trust a measurement.
What to look for in a desktop speed test app
A useful speed-test kit covers four bases. The apps that work best:
- Separate WAN from LAN measurement. The speed to your ISP is one thing; the speed between your desktop and your NAS is something else. The right tool measures both.
- Run without browser quirks. Browser-based tests are convenient but throttled by the browser’s network stack on heavy loads. A native client or a CLI tool measures the actual link.
- Support repeated, scheduled runs. One snapshot is misleading. The link you paid for varies by time of day; useful tools log results over a day or a week.
- Expose latency and packet loss, not just throughput. Bandwidth tells you half the story. A 1 Gbps link with 5% packet loss is unusable for video calls.
- Stay free and open source where possible. Self-hosted speed tests give you a measurement nobody can tilt.
Quick comparison
| App | Best for | Platforms | Free plan | Open source |
|---|---|---|---|---|
| Speedtest by Ookla | Quick WAN snapshot anyone can run | Windows, macOS, Linux | Yes | No |
| iPerf3 | Real LAN measurement between two devices | Windows, macOS, Linux | Yes | Yes (BSD) |
| LibreSpeed | Self-hosted speed test under your control | Web + CLI on all OSes | Yes | Yes (LGPL) |
| Fast.com | Lightweight, Netflix-hosted browser test | Browser on all OSes | Yes | No |
| NetBeez | Continuous monitoring for SMB networks | Windows, macOS, Linux | 30-day trial | No |
| OpenSpeedTest | Browser-based self-hosted alternative | Web + Docker | Yes | Yes (AGPL) |
| Wireshark | Per-packet diagnosis when a test isn’t enough | Windows, macOS, Linux | Yes | Yes (GPL) |
The 7 best desktop internet speed testing apps
1. Speedtest by Ookla — best quick WAN check
Speedtest by Ookla is the consumer speed test everybody knows, and the desktop client is more useful than the web version. It runs on Windows, macOS, and Linux, picks a server near you, and produces the download, upload, ping, and jitter triple you need to settle an argument with your ISP. The 2025 desktop release added a multi-connection mode that better matches real-world TCP behaviour.
The 2026 release added VPN-bypass detection and a server-selection panel so you can pick exactly which test point you want to measure against.
Where it falls short: Ad-supported on the free tier. The “result” implicitly favours single-flow TCP, which doesn’t match how most real workloads use a link. ISPs can prioritise traffic to Ookla servers, which is the long-running fairness complaint.
Pricing:
- Free: full functionality with ads
- Paid: Speedtest VPN bundles for a few dollars a month
Platforms: Windows, macOS, Linux desktop clients; iOS and Android apps.
Download: Speedtest desktop
Bottom line: Run this first. For a 30-second sanity check of your WAN link, nothing is faster.
2. iPerf3 — best LAN bandwidth measurement
iPerf3 is the open-source CLI tool network engineers reach for when they want to know what a link actually does between two specific devices. Run iPerf3 in server mode on one machine, client mode on the other, and measure the throughput, the parallel-stream behaviour, and the loss rate over a controllable window. Want to know if your NAS-to-desktop link maxes out the 2.5 GbE switch? iPerf3 between the two answers in 30 seconds.
The maintained 3.x release line works on every desktop OS and embedded Linux distribution that matters, so the same tool runs on your router, your homelab, and your laptop.
Where it falls short: CLI-only. Two devices required. Some firewalls block iPerf’s default port; you’ll need to allow port 5201 or pick a custom one.
Pricing:
- Free, open source under BSD
Platforms: Windows, macOS, Linux, FreeBSD, plus embedded builds.
Download: iPerf3
Bottom line: The tool that tells you the cable Ethernet swap actually fixed the problem.
3. LibreSpeed — best self-hosted speed test
LibreSpeed is the open-source, self-hosted speed test you run on your own server. Drop it on a VPS, point your devices at it, and measure WAN performance against a server you control rather than Ookla’s pool. The PHP backend is simple to deploy; the JavaScript frontend runs in any browser; a CLI client exists for headless setups.
For homelab operators who want a speed test that isn’t biased by ISP prioritisation, LibreSpeed is the standard answer.
Where it falls short: The result quality depends entirely on the server you host it on. Geographically distant or undersized servers give misleading readings.
Pricing:
- Free, open source under LGPL-3.0
Platforms: Self-host on Linux (Docker or bare PHP); clients on any browser plus the CLI.
Download: LibreSpeed
Bottom line: The right pick when you want a speed test nobody can tilt.
4. Fast.com — best zero-friction browser test
Fast.com is Netflix’s stripped-down speed test. Open the page, the test runs automatically, and you see a download number within five seconds. Click “Show more info” for upload, ping, and connection details. It’s the test that runs without a desktop install, an ad, or a sign-up — useful when you need to measure a friend’s network without explaining anything.
Because the measurement runs against Netflix’s CDN, it’s also a reasonable proxy for streaming-class throughput specifically.
Where it falls short: Browser-based, so the browser’s network stack imposes a cap on heavy loads. No history, no logging, no scheduled runs.
Pricing:
- Free
Platforms: Any browser on any OS.
Download: Fast.com
Bottom line: The right pick for a five-second sanity check.
5. NetBeez — best continuous SMB monitoring
NetBeez is the speed-and-latency monitoring service built for distributed offices, with hardware or virtual probes that measure continuously instead of on-demand. The desktop client is the dashboard for the probes. For network operators running a multi-site SMB, NetBeez gives you a real timeline of WAN performance per site rather than the snapshot a manual speed test produces.
Where it falls short: Commercial product with subscription pricing. Overkill for a single-home network. The probes need network reach to the central NetBeez backend.
Pricing:
- Free: 30-day trial
- Paid: per-probe subscription, contact sales for SMB tiers
Platforms: Windows, macOS, Linux dashboard; Linux-based probes.
Download: NetBeez
Bottom line: The right pick when “is the link actually flaky?” is a multi-site, ongoing question.
6. OpenSpeedTest — best self-hosted browser test
OpenSpeedTest is the second self-hosted option worth knowing about. The Docker image deploys in 30 seconds, supports HTTPS out of the box, and gives you a clean web UI that anyone on your LAN can open in a browser. Where LibreSpeed leans toward server-side PHP, OpenSpeedTest is a single-container drop-in that runs on a Raspberry Pi 5 without breaking a sweat.
Where it falls short: Same caveat as LibreSpeed: results are only as good as the server you host it on. The free version has a usage cap; the unlimited tier has a small one-time fee.
Pricing:
- Free: self-hosted Docker image with daily usage cap
- Paid: lifetime upgrade is a small one-time payment
Platforms: Self-host on Linux (Docker); clients on any browser.
Download: OpenSpeedTest
Bottom line: The right pick when you want a self-hosted speed test running in five minutes.
7. Wireshark — best deep-diagnosis tool
Wireshark isn’t a speed test. It’s the packet-level forensics tool you reach for when a speed test is fine but the network still feels broken. Capture traffic on the interface, filter for the problem flow, and you’ll see retransmits, malformed frames, MTU mismatches, and DNS failures the speed test can’t surface. Pair it with iPerf3, and you have the complete diagnosis kit: bandwidth measurement plus packet-level explanation when the number is wrong.
Where it falls short: Steep learning curve. The interface assumes you know what you’re looking for. Live capture on macOS and Linux requires elevated permissions.
Pricing:
- Free, open source under GPL
Platforms: Windows, macOS, Linux.
Download: Wireshark
Bottom line: The tool you reach for when the speed test is fine but the symptom isn’t.
How to pick the right speed test
- If you want the simplest sanity check: Speedtest by Ookla desktop client.
- If you need to measure LAN between two devices: iPerf3.
- If you want a self-hosted test: LibreSpeed or OpenSpeedTest, depending on whether you prefer PHP or Docker.
- If you don’t want to install anything: Fast.com in any browser.
- If you operate multiple sites: NetBeez for continuous monitoring.
- If the speed test is fine but the network isn’t: Wireshark on the suspect path.
FAQ
What is the best free speed test app for desktop?
Speedtest by Ookla for a quick WAN snapshot, iPerf3 for LAN measurement between two devices, and LibreSpeed or OpenSpeedTest if you want to self-host. All are free; iPerf3 and LibreSpeed are open source.
Are browser-based speed tests accurate?
Within their limits. The browser’s network stack and the test server’s location both affect the result. For a 30-second sanity check, Fast.com or speedtest.net in a browser is fine; for serious troubleshooting, run a native client or iPerf3.
Why is my actual speed lower than what my ISP advertises?
The advertised number is the theoretical maximum; the number you receive depends on your modem, router, switches, cables, Wi-Fi access points, and the local node congestion. Running iPerf3 between your desktop and another wired device on your LAN isolates the LAN-side performance from the ISP question.
Can I run a speed test from the command line?
Yes. Ookla ships a CLI client (speedtest), LibreSpeed has a CLI binary, and iPerf3 is CLI-only. For continuous monitoring scripts, the CLI tools are the right pick.
How often should I run a speed test?
Once when you set up a new network or after a hardware change. Continuously if you suspect intermittent issues — NetBeez handles this professionally, or a cron job that runs speedtest every 15 minutes and logs to a file is the DIY version.
Do speed tests work over a VPN?
Yes, but the result measures the VPN path, not your raw ISP link. To measure both, run the test once with the VPN off and once with it on; the difference is the VPN overhead.
