Latency Impact Calculator
Plug in your ping, jitter and packet loss, pick what you are actually trying to do online, and find out whether the line is up to it. The verdict and 0-100 score are honest, the maths is shown, and the use cases are tuned the way real applications behave.
Explain like I'm 5 (what even is this calculator?)
Speed tests tell you how fat the pipe is. They don't tell you how snappy it is. This calculator looks at the snappy bits: how long round-trips take, how steady that timing is, and whether packets get dropped. Then it tells you whether that's good enough for the thing you actually want to do, like cloud gaming, a video call, or just opening web pages.
Assess your latency
Fill in the form and press the button to see the verdict.
Verdict:
Quality score: / 100
Single-flow TCP throughput cap:
Why this verdict
Prove it
The maths and thresholds, end to end, so you can audit it. RTT, jitter and loss are each compared to the band edges for the use case. The worst band wins the verdict. The 0-100 score is a weighted average across all three.
TCP throughput cap uses the Mathis-lite formula: window divided by RTT, bounded by the line speed. Use-case thresholds are tuned to match how the applications actually feel: cloud gaming and competitive FPS are strict, MMOs and web browsing are forgiving, video and SSH sit in between.
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Latency too high for what you need?
Full fibre (FTTP) gives the best latency floor of any consumer broadband, usually 5 to 10 ms to the nearest peering point, with low jitter and steady performance under load.
Compare full-fibre broadband at broadband.co.ukWhy ping alone is the wrong question
Ask anyone what makes a connection "good for gaming" and you will hear a single number: ping. The truth is that ping is one of three numbers, and on its own it is misleading. A line at 25 ms ping with 20 ms jitter feels worse than a line at 60 ms ping with 2 ms jitter, because the brain notices the wobble more than it notices the average. Add packet loss into the mix and you have a third axis: even a fast, steady line that drops 1 in 50 packets will stutter through a video call. This calculator looks at all three and ranks them against the thing you are actually trying to do.
Why use cases matter
Cloud gaming runs the whole game on a server somewhere and streams the video back to you, so it has to pay the round-trip on every frame. Anything over 60 ms is uncomfortable, anything over 80 ms is unplayable. Competitive FPS gaming is a little more forgiving because the local client predicts movement, so 100 ms is still sort of playable, just not winnable. MMOs and casual online games tolerate 200 ms because the simulation is slower-paced and tick-rate-limited. Video calls put up with 150 ms because audio buffering smooths the worst of it. SSH and remote desktop care most about jitter, because a steady 100 ms ping feels normal but variable jitter makes typing feel rubbery. The same set of numbers therefore gives a different verdict for each use case, which is exactly what the calculator does.
The TCP throughput cap nobody mentions
You can have a 1 Gbps line, a perfect speed test, and a single download that crawls along at 5 Mbps. The reason is the bandwidth-delay product. A single TCP connection can only have one window's worth of data in flight at a time, and on a 100 ms link with a 64 KB window that maths out to roughly 5.2 Mbps. Long-haul downloads from far-away servers run into this all the time. Modern operating systems use window scaling, BBR, and parallel connections to work around it, but the textbook number is still the right reference when one specific download feels stuck. The calculator surfaces the cap so you can sanity-check whether your "slow internet" is actually a TCP-window problem.
What the verdicts mean
- Excellent: the line is well within tolerance for the chosen use case. Nobody in the house will complain.
- Good: not flawless, but solid. You will not notice an issue under normal use.
- Playable: usable, but on the edge. A bad-luck spike will be noticeable.
- Poor: the experience will be visibly compromised. Calls drop frames, games rubber-band, SSH feels laggy.
- Unusable: the chosen activity is not realistic on this line. Switch to a less demanding use, or change the connection.
Common ways to lower latency
- Wire in. Wi-Fi adds 5 to 30 ms of jitter on a busy household network. An ethernet cable is the single biggest improvement most people can make.
- Pick a closer game server. 200 ms to a US East server from the UK is geography, not your line.
- Avoid VPNs for real-time work. Every extra hop adds latency. If you must, use one with a nearby exit node.
- Stop background uploads. A cloud backup or photo sync saturating the upload can ruin ping for everyone in the house.
- Switch to full fibre. FTTP has the lowest latency floor of any consumer broadband, well below FTTC, cable, or fixed wireless.
Related calculators
Latency is the hidden axis behind speed. These cover the rest of the line.
Frequently asked questions
What counts as good ping?
It depends on what you are doing. Under 30 ms is excellent for competitive shooters. 50 to 100 ms is fine for video calls and web browsing. 200 ms is still playable for MMOs and casual gaming. Cloud gaming is the strictest case: anything over 60 ms is uncomfortable.
Why does jitter matter as much as ping?
Ping is the average. Jitter is the variation around it. Real-time apps notice the wobble more than the steady delay. A line with 30 ms ping and 25 ms jitter feels rubbery and unpredictable; the same average with 2 ms jitter feels rock-solid.
What is packet loss and how much is too much?
Packet loss is the percentage of packets that never arrive. Above 1% is noticeable on calls and games. Above 2% is obvious: dropouts, rubber-banding, retransmits. Persistent loss above 1% is worth raising with your provider, even when speed tests look fine.
Why does the calculator show a TCP throughput cap?
A single TCP connection cannot exceed its window size divided by its round-trip time. With a 64 KB window and 100 ms RTT, that is about 5.2 Mbps regardless of line speed. It explains why one download can feel slow even on a fast connection.
How can I lower my latency?
Wire in instead of using Wi-Fi. Pick game servers close to you. Skip VPNs for real-time work. Stop background uploads while gaming or calling. If the line itself is the problem, full fibre has the lowest latency floor of any consumer broadband.