Network & QoS
Latency (VoIP)
By Myroslav Orshak · operates licensed carrier infrastructure · Updated September 2026
Latency is the time between someone speaking and the other person hearing it — and on a phone call, anything beyond roughly 150 milliseconds one way starts making conversation awkward.
How it works
Every step of a call adds a little delay. Your phone gathers 20 milliseconds of audio before it can send anything, the packet crosses the network, the receiving end holds it briefly in a jitter buffer to smooth out uneven arrivals, and then it plays. Distance sets the floor — light through fiber needs about 5 milliseconds per thousand kilometres, and real routes are never straight — but on most business calls the network is the smaller contributor.
The number usually quoted from a ping test is round-trip: there and back. One-way latency, which is what conversation actually experiences, is roughly half of it. That distinction matters, because a 90 ms ping sounds alarming and is in fact perfectly comfortable.
Why it matters
Latency does not make a call sound bad — it makes it feel bad. Audio stays crisp, but the natural rhythm of conversation breaks: people begin talking over each other, pauses feel loaded, and both sides start saying "sorry, go ahead". Under about 150 ms one way nobody notices. By 300 ms, everyone does, and calls acquire that satellite-interview quality.
It is also the impairment you have least control over, which is worth knowing before you spend money chasing it. You cannot shorten the distance to a provider's data center. What you can control is everything that adds delay locally: an overloaded router, a saturated connection forcing packets to queue, and jitter — which forces the buffer to hold audio longer, adding delay as a side effect of instability.
ITU-T G.114 recommends keeping one-way delay under 150 ms for normal conversation and treats 400 ms as the outer limit for any acceptable call. Round-trip figures from a ping test are roughly double the one-way number.
Related terms
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Measure your own delay →Frequently asked questions
What is a good latency for VoIP?
Under 150 ms one way, which is under about 300 ms on a round-trip ping test. Most business connections calling a provider in the same country land between 10 and 50 ms one way — comfortably fine. Problems usually appear only on international calls or genuinely congested links.
Is latency the same as ping?
A ping measures the round trip — out and back. Latency in call-quality terms means one way, so halve your ping figure to compare it against the 150 ms threshold. This is why a 100 ms ping, which looks bad next to a 150 ms target, is actually fine.
How do I reduce latency?
Fix what is local, because the rest is physics. Use a wired connection, keep the link from saturating, and turn on QoS so voice is not queued behind downloads. Reducing jitter helps too — an unstable connection forces the jitter buffer to hold audio longer, which adds delay indirectly. What you cannot change is distance to the provider.
Why do calls to other countries feel delayed?
Distance and routing. Light in fiber covers roughly 200 km per millisecond, and real network paths wander considerably further than the straight line. A call between New York and London spends roughly 35–40 ms each way in transit, 70–80 ms round trip, before anything else is added: still comfortable, but with less headroom for local problems.